diff --git a/_extensions/shafayetShafee/downloadthis/_extension.yml b/_extensions/shafayetShafee/downloadthis/_extension.yml
new file mode 100644
index 0000000..6299f54
--- /dev/null
+++ b/_extensions/shafayetShafee/downloadthis/_extension.yml
@@ -0,0 +1,8 @@
+title: Downloadthis
+author: Shafayet Khan Shafee
+version: 1.1.0
+quarto-required: ">=1.2.0"
+contributes:
+  shortcodes:
+    - downloadthis.lua
+
diff --git a/_extensions/shafayetShafee/downloadthis/downloadthis.lua b/_extensions/shafayetShafee/downloadthis/downloadthis.lua
new file mode 100644
index 0000000..5219082
--- /dev/null
+++ b/_extensions/shafayetShafee/downloadthis/downloadthis.lua
@@ -0,0 +1,121 @@
+--[[
+MIT License
+
+Copyright (c) 2023 Shafayet Khan Shafee
+
+Permission is hereby granted, free of charge, to any person obtaining a copy
+of this software and associated documentation files (the "Software"), to deal
+in the Software without restriction, including without limitation the rights
+to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+copies of the Software, and to permit persons to whom the Software is
+furnished to do so, subject to the following conditions:
+
+The above copyright notice and this permission notice shall be included in all
+copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+SOFTWARE.
+]]--
+
+
+
+local str = pandoc.utils.stringify
+--local p = quarto.log.output
+
+local function ensureHtmlDeps()
+  quarto.doc.add_html_dependency({
+    name = "downloadthis",
+    version = "1.9.1",
+    stylesheets = {"resources/css/downloadthis.css"}
+  })
+end
+
+local function optional(arg, default)
+  if arg == nil or arg == ""
+  then
+    return default
+  else
+    return arg
+  end
+end
+
+function import(script)
+  local path = PANDOC_SCRIPT_FILE:match("(.*[/\\])")
+  package.path = path .. script .. ";" .. package.path
+  return require(script)
+end
+
+local puremagic = import("puremagic.lua")
+
+return {
+  ['downloadthis'] = function(args, kwargs, meta) 
+    
+    -- args and kwargs    
+    local file_path = str(args[1])
+    local extension = "." .. file_path:match("[^.]+$")
+    local dname = optional(str(kwargs["dname"]), "file")
+    local dfilename = dname .. extension
+    local btn_label = " " .. optional(str(kwargs["label"]), "Download") .. " "
+    local btn_type = optional(str(kwargs["type"]), "default")
+    local icon = optional(str(kwargs["icon"]), "download")
+    local class = " " .. optional(str(kwargs["class"]), "")
+    local rand = "dnldts" .. str(math.random(1, 65000))
+    local id = optional(str(kwargs["id"]), rand)
+    -- reading files
+    local fh = io.open(file_path, "rb")
+    if not fh then
+        io.stderr:write("Cannot open file " .. 
+          file_path .. 
+          " | Skipping adding buttons\n")
+        return pandoc.Null()
+    else
+      local contents = fh:read("*all")
+      fh:close()
+      
+      -- creating dataURI object
+      local b64_encoded = quarto.base64.encode(contents)
+      local mimetype = puremagic.via_path(file_path)
+      local data_uri = 'data:' .. mimetype .. ";base64," .. b64_encoded
+      
+      -- js code taken from
+      -- https://github.com/fmmattioni/downloadthis/blob/master/R/utils.R#L59
+      local js = [[fetch('%s').then(res => res.blob()).then(blob => {
+      const downloadURL = window.URL.createObjectURL(blob);
+      const a = document.createElement('a');
+      document.body.appendChild(a);
+      a.href = downloadURL;
+      a.download = '%s'; a.click();
+      window.URL.revokeObjectURL(downloadURL);
+      document.body.removeChild(a);
+        });]]
+      
+      local clicked = js:format(data_uri, dfilename)
+      
+      -- creating button
+      local button = 
+          "<button class=\"btn btn-" .. btn_type .. " downloadthis " .. 
+          class .. "\"" ..
+          " id=\"" .. id .. "\"" ..
+          "><i class=\"bi bi-" .. icon .. "\"" .. "></i>" ..
+          btn_label .. 
+          "</button>"
+      if quarto.doc.is_format("html:js") and quarto.doc.has_bootstrap()
+      then
+        ensureHtmlDeps()
+        return pandoc.RawInline('html',
+        "<a href=\"#" .. id .. "\"" ..
+        " onclick=\"" .. clicked .. "\">" .. button .. "</a>"
+        )
+      else
+        return pandoc.Null()
+      end
+    end
+  end
+}
+
+
diff --git a/_extensions/shafayetShafee/downloadthis/puremagic.lua b/_extensions/shafayetShafee/downloadthis/puremagic.lua
new file mode 100644
index 0000000..4420292
--- /dev/null
+++ b/_extensions/shafayetShafee/downloadthis/puremagic.lua
@@ -0,0 +1,735 @@
+-- puremagic 1.0.1
+-- Copyright (c) 2014 Will Bond <will@wbond.net>
+-- Licensed under the MIT license.
+
+
+function basename(path)
+    local basename_match = path:match('[/\\]([^/\\]+)$')
+    if basename_match then
+        return basename_match, nil
+    end
+
+    return path, nil
+end
+
+
+function extension(path)
+    path = path:lower()
+    local tar_match = path:match('%.(tar%.[^.]+)$')
+    if tar_match then
+        return tar_match
+    end
+    if path:sub(#path - 11, #path) == '.numbers.zip' then
+        return 'numbers.zip'
+    end
+    if path:sub(#path - 9, #path) == '.pages.zip' then
+        return 'pages.zip'
+    end
+    if path:sub(#path - 7, #path) == '.key.zip' then
+        return 'key.zip'
+    end
+    return path:match('%.([^.]+)$')
+end
+
+
+function in_table(value, list)
+    for i=1, #list do
+        if list[i] == value then
+            return true
+        end
+    end
+    return false
+end
+
+
+function string_to_bit_table(chars)
+    local output = {}
+    for char in chars:gmatch('.') do
+        local num = string.byte(char)
+        local bits = {0, 0, 0, 0, 0, 0, 0, 0}
+        for bit=8, 1, -1 do
+            if num > 0 then
+                bits[bit] = math.fmod(num, 2)
+                num = (num - bits[bit]) / 2
+            end
+        end
+        table.insert(output, bits)
+    end
+    return output
+end
+
+
+function bit_table_to_string(bits)
+    local output = {}
+    for i = 1, #bits do
+        local num = tonumber(table.concat(bits[i]), 2)
+        table.insert(output, string.format('%c', num))
+    end
+    return table.concat(output)
+end
+
+
+function bitwise_and(a, b)
+    local a_bytes = string_to_bit_table(a)
+    local b_bytes = string_to_bit_table(b)
+
+    local output = {}
+    for i = 1, #a_bytes do
+        local bits = {0, 0, 0, 0, 0, 0, 0, 0}
+        for j = 1, 8 do
+            if a_bytes[i][j] == 1 and b_bytes[i][j] == 1 then
+                bits[j] = 1
+            else
+                bits[j] = 0
+            end
+        end
+        table.insert(output, bits)
+    end
+
+    return bit_table_to_string(output)
+end
+
+
+-- Unpack a little endian byte string into an integer
+function unpack_le(chars)
+    local bit_table = string_to_bit_table(chars)
+    -- Merge the bits into a string of 1s and 0s
+    local result = {}
+    for i=1, #bit_table do
+        result[#chars + 1 - i] = table.concat(bit_table[i])
+    end
+    return tonumber(table.concat(result), 2)
+end
+
+
+-- Unpack a big endian byte string into an integer
+function unpack_be(chars)
+    local bit_table = string_to_bit_table(chars)
+    -- Merge the bits into a string of 1s and 0s
+    for i=1, #bit_table do
+        bit_table[i] = table.concat(bit_table[i])
+    end
+    return tonumber(table.concat(bit_table), 2)
+end
+
+
+-- Takes the first 4-8k of an EBML file and identifies if it is matroska or webm
+-- and it it contains just video or just audio.
+function ebml_parse(content)
+    local position = 1
+    local length = #content
+
+    local header_token, header_value, used_bytes = ebml_parse_section(content)
+    position = position + used_bytes
+
+
+    if header_token ~= '\x1AE\xDF\xA3' then
+        return nil, 'Unable to find EBML ID'
+    end
+
+    -- The matroska spec sets the default doctype to be 'matroska', however
+    -- many file specify this anyway. The other option is 'webm'.
+    local doctype = 'matroska'
+    if header_value['B\x82'] then
+        doctype = header_value['B\x82']
+    end
+
+    if doctype ~= 'matroska' and doctype ~= 'webm' then
+        return nil, 'Unknown EBML doctype'
+    end
+
+    local segment_position = nil
+    local track_position = nil
+    local has_video = false
+    local found_tracks = false
+
+    while position <= length do
+        local ebml_id, ebml_value, used_bytes = ebml_parse_section(content:sub(position, length))
+        position = position + used_bytes
+
+        -- Segment
+        if ebml_id == '\x18S\x80g' then
+            segment_position = position
+        end
+
+        -- Meta seek information
+        if ebml_id == '\x11M\x9Bt' then
+            -- Look for the seek info about the tracks token
+            for i, child in ipairs(ebml_value['M\xBB']) do
+                if child['S\xAB'] == '\x16T\xAEk' then
+                    track_position = segment_position + unpack_be(child['S\xAC'])
+                    position = track_position
+                    break
+                end
+            end
+        end
+
+        -- Track
+        if ebml_id == '\x16T\xAEk' then
+            found_tracks = true
+            -- Scan through each track looking for video
+            for i, child in ipairs(ebml_value['\xAE']) do
+                -- Look to see if the track type is video
+                if unpack_be(child['\x83']) == 1 then
+                    has_video = true
+                    break
+                end
+            end
+            break
+        end
+    end
+
+    if found_tracks and not has_video then
+        if doctype == 'matroska' then
+            return 'audio/x-matroska'
+        else
+            return 'audio/webm'
+        end
+    end
+
+    if doctype == 'matroska' then
+        return 'video/x-matroska'
+    else
+        return 'video/webm'
+    end
+end
+
+
+-- Parses a section of an EBML document, returning the EBML ID at the beginning,
+-- plus the value as a table with child EBML IDs as keys and the number of
+-- bytes from the content that contained the ID and value
+function ebml_parse_section(content)
+    local ebml_id, element_length, used_bytes = ebml_id_and_length(content)
+
+    -- Don't parse the segment since it is the whole file!
+    if ebml_id == '\x18\x53\x80\x67' then
+        return ebml_id, nil, used_bytes
+    end
+
+    local ebml_value = content:sub(used_bytes + 1, used_bytes + element_length)
+    used_bytes = used_bytes + element_length
+
+    -- We always parse the return value of level 0/1 elements
+    local recursive_parse = false
+    if #ebml_id == 4 then
+        recursive_parse = true
+
+    -- We need Seek information
+    elseif ebml_id == '\x4D\xBB' then
+        recursive_parse = true
+
+    -- We want the top-level of TrackEntry to grab the TrackType
+    elseif ebml_id == '\xAE' then
+        recursive_parse = true
+    end
+
+    if recursive_parse then
+        local buffer = ebml_value
+        ebml_value = {}
+
+        -- Track which child entries have been converted to an array
+        local array_children = {}
+
+        while #buffer > 0 do
+            local child_ebml_id, child_ebml_value, child_used_bytes = ebml_parse_section(buffer)
+
+            if array_children[child_ebml_id] then
+                table.insert(ebml_value[child_ebml_id], child_ebml_value)
+
+            -- Single values are just stores by themselves
+            elseif ebml_value[child_ebml_id] == nil then
+                -- Force seek info and tracks to be arrays even if there is only one
+                if child_ebml_id == 'M\xBB' or child_ebml_id == '\xAE' then
+                    child_ebml_value = {child_ebml_value}
+                    array_children[child_ebml_id] = true
+                end
+                ebml_value[child_ebml_id] = child_ebml_value
+
+            -- If there is already a value for the ID, turn it into a table
+            else
+                ebml_value[child_ebml_id] = {ebml_value[child_ebml_id], child_ebml_value}
+                array_children[child_ebml_id] = true
+            end
+
+            -- Move past the part we've parsed
+            buffer = buffer:sub(child_used_bytes + 1, #buffer)
+        end
+    end
+
+    return ebml_id, ebml_value, used_bytes
+end
+
+
+-- Should accept 12+ bytes, will return the ebml id, the data length and the
+-- number of bytes that were used to hold those values.
+function ebml_id_and_length(chars)
+    -- The ID is encoded the same way as the length, however, we don't want
+    -- to remove the length bits from the ID value or intepret it as an
+    -- unsigned int since all of the documentation online references the IDs in
+    -- encoded form.
+    local _, id_length = ebml_length(chars:sub(1, 4))
+    local ebml_id = chars:sub(1, id_length)
+
+    local remaining = chars:sub(id_length + 1, id_length + 8)
+    local element_length, used_bytes = ebml_length(remaining)
+
+    return ebml_id, element_length, id_length + used_bytes
+end
+
+
+-- Should accept 8+ bytes, will return the data length plus the number of bytes
+-- that were used to hold the data length.
+function ebml_length(chars)
+    -- We substring chars to ensure we don't build a huge table we don't need
+    local bit_tables = string_to_bit_table(chars:sub(1, 8))
+
+    local value_length = 1
+    for i=1, #bit_tables[1] do
+        if bit_tables[1][i] == 0 then
+            value_length = value_length + 1
+        else
+            -- Clear the indicator bit so the rest of the byte
+            bit_tables[1][i] = 0
+            break
+        end
+    end
+
+    local bits = {}
+    for i=1, value_length do
+        table.insert(bits, table.concat(bit_tables[i]))
+    end
+
+    return tonumber(table.concat(bits), 2), value_length
+end
+
+
+function binary_tests(content, ext)
+    local length = #content
+    local _1_8   = content:sub(1, 8)
+    local _1_7   = content:sub(1, 7)
+    local _1_6   = content:sub(1, 6)
+    local _1_5   = content:sub(1, 5)
+    local _1_4   = content:sub(1, 4)
+    local _1_3   = content:sub(1, 3)
+    local _1_2   = content:sub(1, 2)
+    local _9_12  = content:sub(9, 12)
+
+
+    -- Images
+    if _1_4 == '\xC5\xD0\xD3\xC6' then
+        -- With a Windows-format EPS, the file starts right after a 30-byte
+        -- header, or a 30-byte header followed by two bytes of padding
+        if content:sub(33, 42) == '%!PS-Adobe' or content:sub(31, 40) == '%!PS-Adobe' then
+            return 'application/postscript'
+        end
+    end
+
+    if _1_8 == '%!PS-Ado' and content:sub(9, 10) == 'be' then
+        return 'application/postscript'
+    end
+
+    if _1_4 == 'MM\x00*' or _1_4 == 'II*\x00' then
+        return 'image/tiff'
+    end
+
+    if _1_8 == '\x89PNG\r\n\x1A\n' then
+        return 'image/png'
+    end
+
+    if _1_6 == 'GIF87a' or _1_6 == 'GIF89a' then
+        return 'image/gif'
+    end
+
+    if _1_4 == 'RIFF' and _9_12 == 'WEBP' then
+        return 'image/webp'
+    end
+
+    if _1_2 == 'BM' and length > 14 and in_table(content:sub(15, 15), {'\x0C', '(', '@', '\x80'}) then
+        return 'image/x-ms-bmp'
+    end
+
+    local normal_jpeg    = length > 10 and in_table(content:sub(7, 10), {'JFIF', 'Exif'})
+    local photoshop_jpeg = length > 24 and _1_4 == '\xFF\xD8\xFF\xED' and content:sub(21, 24) == '8BIM'
+    if normal_jpeg or photoshop_jpeg then
+        return 'image/jpeg'
+    end
+
+    if _1_4 == '8BPS' then
+        return 'image/vnd.adobe.photoshop'
+    end
+
+    if _1_8 == '\x00\x00\x00\x0CjP  ' and _9_12 == '\r\n\x87\n' then
+        return 'image/jp2'
+    end
+
+    if _1_4 == '\x00\x00\x01\x00' then
+        return 'application/vnd.microsoft.icon'
+    end
+
+
+    -- Audio/Video
+    if _1_4 == '\x1AE\xDF\xA3' and length > 1000 then
+        local mimetype, err = ebml_parse(content)
+
+        if mimetype then
+            return mimetype
+        end
+    end
+
+    if _1_4 == 'MOVI' then
+        if in_table(content:sub(5, 8), {'moov', 'mdat'}) then
+            return 'video/quicktime'
+        end
+    end
+
+    if length > 8 and content:sub(5, 8) == 'ftyp' then
+        local lower_9_12 = _9_12:lower()
+
+        if in_table(lower_9_12, {'avc1', 'isom', 'iso2', 'mp41', 'mp42', 'mmp4', 'ndsc', 'ndsh', 'ndsm', 'ndsp', 'ndss', 'ndxc', 'ndxh', 'ndxm', 'ndxp', 'ndxs', 'f4v ', 'f4p ', 'm4v '}) then
+            return 'video/mp4'
+        end
+
+        if in_table(lower_9_12, {'msnv', 'ndas', 'f4a ', 'f4b ', 'm4a ', 'm4b ', 'm4p '}) then
+            return 'audio/mp4'
+        end
+
+        if in_table(lower_9_12, {'3g2a', '3g2b', '3g2c', 'kddi'}) then
+            return 'video/3gpp2'
+        end
+
+        if in_table(lower_9_12, {'3ge6', '3ge7', '3gg6', '3gp1', '3gp2', '3gp3', '3gp4', '3gp5', '3gp6', '3gs7'}) then
+            return 'video/3gpp'
+        end
+
+        if lower_9_12 == 'mqt ' or lower_9_12 == 'qt  ' then
+            return 'video/quicktime'
+        end
+
+        if lower_9_12 == 'jp2 ' then
+            return 'image/jp2'
+        end
+    end
+
+    -- MP3
+    if bitwise_and(_1_2, '\xFF\xF6') == '\xFF\xF2' then
+        local byte_3 = content:sub(3, 3)
+        if bitwise_and(byte_3, '\xF0') ~= '\xF0' and bitwise_and(byte_3, "\x0C") ~= "\x0C" then
+            return 'audio/mpeg'
+        end
+    end
+    if _1_3 == 'ID3' then
+        return 'audio/mpeg'
+    end
+
+    if _1_4 == 'fLaC' then
+        return 'audio/x-flac'
+    end
+
+    if _1_8 == '0&\xB2u\x8Ef\xCF\x11' then
+        -- Without writing a full-on ASF parser, we can just scan for the
+        -- UTF-16 string "AspectRatio"
+        if content:find('\x00A\x00s\x00p\x00e\x00c\x00t\x00R\x00a\x00t\x00i\x00o', 1, true) then
+            return 'video/x-ms-wmv'
+        end
+        return 'audio/x-ms-wma'
+    end
+
+    if _1_4 == 'RIFF' and _9_12 == 'AVI ' then
+        return 'video/x-msvideo'
+    end
+
+    if _1_4 == 'RIFF' and _9_12 == 'WAVE' then
+        return 'audio/x-wav'
+    end
+
+    if _1_4 == 'FORM' and _9_12 == 'AIFF' then
+        return 'audio/x-aiff'
+    end
+
+    if _1_4 == 'OggS' then
+        local _29_33 = content:sub(29, 33)
+        if _29_33 == '\x01vorb' then
+            return 'audio/vorbis'
+        end
+        if _29_33 == '\x07FLAC' then
+            return 'audio/x-flac'
+        end
+        if _29_33 == 'OpusH' then
+            return 'audio/ogg'
+        end
+        -- Theora and OGM
+        if _29_33 == '\x80theo' or _29_33 == 'vide' then
+            return 'video/ogg'
+        end
+    end
+
+    if _1_3 == 'FWS' or _1_3 == 'CWS' then
+        return 'application/x-shockwave-flash'
+    end
+
+    if _1_3 == 'FLV' then
+        return 'video/x-flv'
+    end
+
+
+    if _1_5 == '%PDF-' then
+        return 'application/pdf'
+    end
+
+    if _1_5 == '{\\rtf' then
+        return 'text/rtf'
+    end
+
+
+    -- Office '97-2003 formats
+    if _1_8 == '\xD0\xCF\x11\xE0\xA1\xB1\x1A\xE1' then
+        if in_table(ext, {'xls', 'csv', 'tab'}) then
+            return 'application/vnd.ms-excel'
+        end
+        if ext == 'ppt' then
+            return 'application/vnd.ms-powerpoint'
+        end
+        -- We default to word since we need something if the extension isn't recognized
+        return 'application/msword'
+    end
+
+    if _1_8 == '\x09\x04\x06\x00\x00\x00\x10\x00' then
+        return 'application/vnd.ms-excel'
+    end
+
+    if _1_6 == '\xDB\xA5\x2D\x00\x00\x00' or _1_5 == '\x50\x4F\x5E\x51\x60' or _1_4 == '\xFE\x37\x00\x23' or _1_3 == '\x94\xA6\x2E' then
+        return 'application/msword'
+    end
+
+    if _1_4 == 'PK\x03\x04' then
+        -- Office XML formats
+        if ext == 'xlsx' then
+            return 'application/vnd.ms-excel'
+        end
+
+        if ext == 'pptx' then
+            return 'application/vnd.ms-powerpoint'
+        end
+
+        if ext == 'docx' then
+            return 'application/msword'
+        end
+
+        -- Open Office formats
+        if ext == 'ods' then
+            return 'application/vnd.oasis.opendocument.spreadsheet'
+        end
+
+        if ext == 'odp' then
+            return 'application/vnd.oasis.opendocument.presentation'
+        end
+
+        if ext == 'odt' then
+            return 'application/vnd.oasis.opendocument.text'
+        end
+
+        -- iWork - some programs like Mac Mail change the filename to
+        -- .numbers.zip, etc
+        if ext == 'pages' or ext == 'pages.zip' then
+          return 'application/vnd.apple.pages'
+        end
+        if ext == 'key' or ext == 'key.zip' then
+            return 'application/vnd.apple.keynote'
+        end
+        if ext == 'numbers' or ext == 'numbers.zip' then
+            return 'application/vnd.apple.numbers'
+        end
+
+        -- Otherwise just a zip
+        return 'application/zip'
+    end
+
+
+    -- Archives
+    if length > 257 then
+        if content:sub(258, 263) == 'ustar\x00' then
+            return 'application/x-tar'
+        end
+        if content:sub(258, 265) == 'ustar\x40\x40\x00' then
+            return 'application/x-tar'
+        end
+    end
+
+    if _1_7 == 'Rar!\x1A\x07\x00' or _1_8 == 'Rar!\x1A\x07\x01\x00' then
+        return 'application/x-rar-compressed'
+    end
+
+    if _1_2 == '\x1F\x9D' then
+        return 'application/x-compress'
+    end
+
+    if _1_2 == '\x1F\x8B' then
+        return 'application/x-gzip'
+    end
+
+    if _1_3 == 'BZh' then
+        return 'application/x-bzip2'
+    end
+
+    if _1_6 == '\xFD7zXZ\x00' then
+        return 'application/x-xz'
+    end
+
+    if _1_6 == '7z\xBC\xAF\x27\x1C' then
+        return 'application/x-7z-compressed'
+    end
+
+    if _1_2 == 'MZ' then
+        local pe_header_start = unpack_le(content:sub(61, 64))
+        local signature = content:sub(pe_header_start + 1, pe_header_start + 4)
+
+        if signature == 'PE\x00\x00' then
+            local image_file_header_start = pe_header_start + 5
+            local characteristics = content:sub(image_file_header_start + 18, image_file_header_start + 19)
+            local is_dll = bitwise_and(characteristics, '\x20\x00') == '\x20\x00'
+
+            if is_dll then
+                return 'application/x-msdownload'
+            end
+
+            return 'application/octet-stream'
+        end
+    end
+
+    return nil
+end
+
+
+function text_tests(content)
+    local lower_content = content:lower()
+
+    if content:find('^%%!PS-Adobe') then
+        return 'application/postscript'
+    end
+
+    if lower_content:find('<?php', 1, true) or content:find('<?=', 1, true) then
+        return 'application/x-httpd-php'
+    end
+
+    if lower_content:find('^%s*<%?xml') then
+        if content:find('<svg') then
+            return 'image/svg+xml'
+        end
+        if lower_content:find('<!doctype html') then
+            return 'application/xhtml+xml'
+        end
+        if content:find('<rss') then
+            return 'application/rss+xml'
+        end
+        return 'application/xml'
+    end
+
+    if lower_content:find('^%s*<html') or lower_content:find('^%s*<!doctype') then
+        return 'text/html'
+    end
+
+    if lower_content:find('^#![/a-z0-9]+ ?python') then
+        return 'application/x-python'
+    end
+
+    if lower_content:find('^#![/a-z0-9]+ ?perl') then
+        return 'application/x-perl'
+    end
+
+    if lower_content:find('^#![/a-z0-9]+ ?ruby') then
+        return 'application/x-ruby'
+    end
+
+    if lower_content:find('^#![/a-z0-9]+ ?php') then
+        return 'application/x-httpd-php'
+    end
+
+    if lower_content:find('^#![/a-z0-9]+ ?bash') then
+        return 'text/x-shellscript'
+    end
+
+    return nil
+end
+
+
+local ext_map = {
+    css   = 'text/css',
+    csv   = 'text/csv',
+    htm   = 'text/html',
+    html  = 'text/html',
+    xhtml = 'text/html',
+    ics   = 'text/calendar',
+    js    = 'application/javascript',
+    php   = 'application/x-httpd-php',
+    php3  = 'application/x-httpd-php',
+    php4  = 'application/x-httpd-php',
+    php5  = 'application/x-httpd-php',
+    inc   = 'application/x-httpd-php',
+    pl    = 'application/x-perl',
+    cgi   = 'application/x-perl',
+    py    = 'application/x-python',
+    rb    = 'application/x-ruby',
+    rhtml = 'application/x-ruby',
+    rss   = 'application/rss+xml',
+    sh    = 'text/x-shellscript',
+    tab   = 'text/tab-separated-values',
+    vcf   = 'text/x-vcard',
+    xml   = 'application/xml'
+}
+
+function ext_tests(ext)
+    local mimetype = ext_map[ext]
+    if mimetype then
+        return mimetype
+    end
+    return 'text/plain'
+end
+
+
+local _M = {}
+
+
+function _M.via_path(path, filename)
+    local f, err = io.open(path, 'r')
+    if not f then
+        return nil, err
+    end
+
+    local content = f:read(4096)
+    f:close()
+
+    if not filename then
+        filename = basename(path)
+    end
+
+    return _M.via_content(content, filename)
+end
+
+
+function _M.via_content(content, filename)
+    local ext = extension(filename)
+
+    -- If there are no low ASCII chars and no easily distinguishable tokens,
+    -- we need to detect by file extension
+
+    local mimetype = nil
+
+    mimetype = binary_tests(content, ext)
+    if mimetype then
+        return mimetype
+    end
+
+    -- Binary-looking files should have been detected so far
+    if content:find('[%z\x01-\x08\x0B\x0C\x0E-\x1F]') then
+        return 'application/octet-stream'
+    end
+
+    mimetype = text_tests(content)
+    if mimetype then
+        return mimetype
+    end
+
+    return ext_tests(ext)
+end
+
+return _M
\ No newline at end of file
diff --git a/_extensions/shafayetShafee/downloadthis/resources/css/downloadthis.css b/_extensions/shafayetShafee/downloadthis/resources/css/downloadthis.css
new file mode 100644
index 0000000..b9f952c
--- /dev/null
+++ b/_extensions/shafayetShafee/downloadthis/resources/css/downloadthis.css
@@ -0,0 +1,13 @@
+.downloadthis:focus,
+  .downloadthis:active  {
+     box-shadow: none !important;
+  }
+  
+  .downloadthis:hover {
+     transition: 0.2s;
+     filter: brightness(0.90);
+  }
+  
+  .downloadthis:active {
+     filter: brightness(0.80);
+}
\ No newline at end of file
diff --git a/_quarto.yml b/_quarto.yml
index 130dc42..5cf497d 100644
--- a/_quarto.yml
+++ b/_quarto.yml
@@ -1,6 +1,12 @@
 project:
   type: website
   output-dir: _site
+  render:
+    - "**/*.qmd"
+    - "**/*.ipynb"
+    - "!notebooks/"
+  resources:
+    - notebooks/**
 
 website:
   title: "Programación en Python"
@@ -63,11 +69,12 @@ website:
         # - text: Ejemplos
         #   contents:
         #     - recursos/ejemplos/clases.qmd
-        - text: Presentaciones
+        - text: Material de clase
           contents:
-            - recursos/slides/01.qmd
-            - recursos/slides/02_1.qmd
-            - recursos/slides/02_2.qmd
+            - recursos/clases/01.qmd
+            - recursos/clases/02_1.qmd
+            - recursos/clases/02_2.qmd
+            - recursos/clases/04.qmd
         - text: Tutoriales
           contents:
             - recursos/tutoriales/instalacion_python.qmd
diff --git a/notebooks/clase_04.ipynb b/notebooks/clase_04.ipynb
new file mode 100644
index 0000000..e782e68
--- /dev/null
+++ b/notebooks/clase_04.ipynb
@@ -0,0 +1,506 @@
+{
+ "cells": [
+  {
+   "cell_type": "markdown",
+   "id": "b7b2214c",
+   "metadata": {},
+   "source": [
+    "# Programación Orientada a Objetos - Fundamentos"
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "id": "14f8f46f",
+   "metadata": {},
+   "source": [
+    "## Introducción\n",
+    "\n",
+    "- ¿Qué es un objeto y qué no?\n",
+    "- Objetos, atributos y acciones (e.g. TV).\n",
+    "- En programación, anque los objetos no seann elementos físicos, aplican los mismos conceptos."
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "id": "f745478b",
+   "metadata": {},
+   "source": [
+    "## Objetos familiares\n",
+    "\n",
+    "Cadenas y listas, sus atributos y métodos."
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "id": "e95a398e",
+   "metadata": {},
+   "source": [
+    "## Clases y objetos\n",
+    "\n",
+    "- Las clases definen nuevos tipos de objetos (o nuevos tipos de datos).\n",
+    "    - Informal: Plantilla.\n",
+    "- Molde para construir (e.g. budines)"
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "id": "fef605c0",
+   "metadata": {},
+   "source": [
+    "### La clase `dict`\n",
+    "\n",
+    "- Los diccionarios son instancias de la clase `dict`\n",
+    "- Define sus atributos y comportamiento\n",
+    "- Misma clase no significa mismo objeto\n",
+    "    - Clase vs instancia\n",
+    "    - Clase vs tipo de dato\n",
+    "    - Instancia vs objeto"
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "id": "853c30fd",
+   "metadata": {},
+   "source": [
+    "## Creando nuestras propias clases\n",
+    "\n",
+    "- Definimos un nuevo tipo de dato, sus atributos (estado) y lo que puede hacer (comportamiento).\n",
+    "- Sentencia `class` y método `__init__`.\n",
+    "- Creando múltiples instancias de una misma clase."
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "id": "b33d8827",
+   "metadata": {},
+   "source": [
+    "### Parámetros de inicialización\n",
+    "\n",
+    "- `__init__` puede recibe datos al crear un objeto."
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "id": "3b442264",
+   "metadata": {},
+   "source": [
+    "## Atributos\n",
+    "\n",
+    "- Variables asociadas a un objeto que representan su estado.\n",
+    "- Creación de atributos\n",
+    "- Atributos \"opcionales\"\n"
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "id": "0f3cd821",
+   "metadata": {},
+   "source": [
+    "## Métodos\n",
+    "\n",
+    "- Los métodos son las acciones que puede realizar un objeto.\n",
+    "- Conectan comportamiento con el estado almacenado en la instancia.\n",
+    "- Funciones asociaas a una clase determinada.\n",
+    "- El parámetro `self`."
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "id": "b7b695b5",
+   "metadata": {},
+   "source": [
+    "### Que modifican estado\n",
+    "\n",
+    "- Algunos métodos cambian atributos del objeto."
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "id": "f4bc1a08",
+   "metadata": {},
+   "source": [
+    "### Que reciben argumentos\n",
+    "\n",
+    "- Además de `self`, un método puede recibir otros argumentos."
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "id": "8a3abe4d",
+   "metadata": {},
+   "source": [
+    "### Que devuelven resultados\n",
+    "\n",
+    "- Los métodos no son más que funciones, así que pueden calcular y retornar valores.\n",
+    "- No todo método debe modificar el estado interno: algunos solo consultan o derivan información."
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "id": "3b3ac6e1",
+   "metadata": {},
+   "source": [
+    "### Que devuelven al objeto\n",
+    "\n",
+    "- Permiten encadenar llamadas (e.g. método de `str`).\n"
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "id": "67d6f903",
+   "metadata": {},
+   "source": [
+    "## Ejemplo: Cuenta bancaria\n",
+    "\n",
+    "Para concluir, vamos a implementar una clase que represente de forma sencilla una cuenta bancaria.\n",
+    "\n",
+    "En este modelo simplificado, cada cuenta tendrá tres atributos:\n",
+    "\n",
+    "* `titular`: el nombre de la persona dueña de la cuenta\n",
+    "* `saldo`: el dinero disponible en la cuenta\n",
+    "* `moneda`: el tipo de moneda en el que está expresado el saldo (por ejemplo, `\"ARS\"` o `\"USD\"`)\n",
+    "\n",
+    "Además, la clase contará con métodos que permitan realizar operaciones básicas:\n",
+    "\n",
+    "* `depositar`: suma dinero al saldo actual\n",
+    "* `retirar`: descuenta dinero del saldo, si hay fondos suficientes\n",
+    "* `transferir`: mueve dinero de una cuenta a otra\n",
+    "* `resumen`: muestra el estado actual de la cuenta de forma clara y legible"
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "id": "06b2c4d4",
+   "metadata": {},
+   "source": [
+    "# Programación Orientada a Objetos - Encapsulamiento"
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "id": "5dd9b75c",
+   "metadata": {},
+   "source": [
+    "## Las múltiples caras del encapsulamiento"
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "id": "e20655db",
+   "metadata": {},
+   "source": [
+    "- Funciones y objetos\n",
+    "- Objetos\n",
+    "    - Interior vs exterior"
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "id": "c1b62f3b",
+   "metadata": {},
+   "source": [
+    "## Interfaces claras"
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "id": "7fdb8e80",
+   "metadata": {},
+   "source": [
+    "### A través de _docstrings_"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": null,
+   "id": "5c56f8a8",
+   "metadata": {},
+   "outputs": [],
+   "source": [
+    "class CuentaBancaria:\n",
+    "    \"\"\"Cuenta bancaria simple con operaciones básicas.\n",
+    "\n",
+    "    Esta clase implementa un modelo básico de cuenta bancaria que permite\n",
+    "    depositar y retirar dinero, así como consultar el saldo actual.\n",
+    "    \"\"\"\n",
+    "    def __init__(self, titular, saldo_inicial=0.0):\n",
+    "        \"\"\"Inicializa una nueva cuenta bancaria.\n",
+    "\n",
+    "        Parameters\n",
+    "        ----------\n",
+    "        titular : str\n",
+    "            Nombre del titular de la cuenta.\n",
+    "        saldo_inicial : float, optional\n",
+    "            Saldo inicial de la cuenta. Por defecto es 0.0.\n",
+    "        \"\"\"\n",
+    "        self.titular = titular\n",
+    "        self.saldo = saldo_inicial\n",
+    "\n",
+    "    def depositar(self, monto):\n",
+    "        \"\"\"Depositar dinero en la cuenta.\n",
+    "\n",
+    "        Parameters\n",
+    "        ----------\n",
+    "        monto : float\n",
+    "            Monto a depositar. Debe ser un número positivo.\n",
+    "        \"\"\"\n",
+    "        if monto <= 0:\n",
+    "            print(\"Error: El monto a depositar debe ser positivo.\")\n",
+    "            return\n",
+    "        self.saldo += monto\n",
+    "\n",
+    "\n",
+    "    def retirar(self, monto):\n",
+    "        \"\"\"Extrae dinero de la cuenta si hay fondos suficientes.\n",
+    "\n",
+    "        Parameters\n",
+    "        ----------\n",
+    "        monto : float\n",
+    "            Monto a retirar.\n",
+    "        \"\"\"\n",
+    "        if monto > self.saldo:\n",
+    "            print(\"Error: Fondos insuficientes.\")\n",
+    "            return\n",
+    "        self.saldo -= monto\n",
+    "\n",
+    "\n",
+    "    def consultar_saldo(self):\n",
+    "        \"\"\"Devuelve el saldo actual.\n",
+    "\n",
+    "        Returns\n",
+    "        -------\n",
+    "        float\n",
+    "            Saldo disponible en la cuenta.\n",
+    "        \"\"\"\n",
+    "        return self.saldo"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": null,
+   "id": "3cb891e0",
+   "metadata": {},
+   "outputs": [],
+   "source": [
+    "help(CuentaBancaria)"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": null,
+   "id": "d8150810",
+   "metadata": {},
+   "outputs": [],
+   "source": [
+    "help(CuentaBancaria.depositar)"
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "id": "8da90f1d",
+   "metadata": {},
+   "source": [
+    "### Anotaciones de tipo"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": null,
+   "id": "58d7afd8",
+   "metadata": {},
+   "outputs": [],
+   "source": [
+    "def saludar(nombre: str) -> str:\n",
+    "    return f\"¡Hola, {nombre}!\"\n",
+    "\n",
+    "saludar(\"Guido\")"
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "id": "2d0a047f",
+   "metadata": {},
+   "source": [
+    "## Estrategias de encapsulamiento"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 1,
+   "id": "d29cdf62",
+   "metadata": {},
+   "outputs": [],
+   "source": [
+    "class Estudiante:\n",
+    "    def __init__(self, nombre, ingreso, carrera):\n",
+    "        self.nombre = nombre\n",
+    "        self.ingreso = ingreso\n",
+    "        self.carrera = carrera\n",
+    "\n",
+    "    def resumen(self):\n",
+    "        return f\"Estudiante(nombre={self.nombre}, ingreso={self.ingreso}, carrera={self.carrera})\""
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "id": "7cbbda52",
+   "metadata": {},
+   "source": [
+    "### _Setters_ y _getters_"
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "id": "dda85bce",
+   "metadata": {},
+   "source": [
+    "### Atributos \"protegidos\""
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "id": "85a2ecc2",
+   "metadata": {},
+   "source": [
+    "### Atributos \"\"\"privados\"\"\""
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "id": "a4d6b4ea",
+   "metadata": {},
+   "source": [
+    "### Cuasi-atributos (el decorador `@property`)"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": null,
+   "id": "8aa6c79b",
+   "metadata": {},
+   "outputs": [],
+   "source": [
+    "class Estudiante:\n",
+    "    def __init__(self, nombre):\n",
+    "        self.nombre = nombre\n",
+    "\n",
+    "    @property\n",
+    "    def nombre(self):\n",
+    "        return self._nombre\n",
+    "\n",
+    "    @nombre.setter\n",
+    "    def nombre(self, valor):\n",
+    "        if isinstance(valor, str):\n",
+    "            self._nombre = valor\n",
+    "        else:\n",
+    "            print(\"El nombre debe ser de tipo 'str'\")\n",
+    "\n",
+    "    def resumen(self):\n",
+    "        return f\"Estudiante(nombre={self.nombre})\""
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "id": "725e0d3b",
+   "metadata": {},
+   "source": [
+    "## Atributos y métodos de clase"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": null,
+   "id": "30c08ada",
+   "metadata": {},
+   "outputs": [],
+   "source": [
+    "class Gato:\n",
+    "    especie = \"Felis catus\"\n",
+    "\n",
+    "    def __init__(self, nombre, raza=None):\n",
+    "        self.nombre = nombre\n",
+    "        self.raza = raza\n",
+    "\n",
+    "    def resumen(self):\n",
+    "        return f\"Gato(nombre={self.nombre}, raza={self.raza})\""
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": null,
+   "id": "7a7418fc",
+   "metadata": {},
+   "outputs": [],
+   "source": [
+    "class Perro:\n",
+    "    especie = \"Canis lupus familiaris\"\n",
+    "\n",
+    "    def __init__(self, nombre, raza=None):\n",
+    "        self.nombre = nombre\n",
+    "        self.raza = raza\n",
+    "\n",
+    "    def resumen(self):\n",
+    "        return f\"Perro(nombre={self.nombre}, raza={self.raza})\""
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "id": "cba8a2be",
+   "metadata": {},
+   "source": [
+    "Otro ejemplo..."
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": null,
+   "id": "b4e8e09d",
+   "metadata": {},
+   "outputs": [],
+   "source": [
+    "class Usuario:\n",
+    "    total_usuarios = 0\n",
+    "\n",
+    "    def __init__(self, nombre):\n",
+    "        self.nombre = nombre\n",
+    "        Usuario.total_usuarios += 1"
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "id": "c316542e",
+   "metadata": {},
+   "source": [
+    "El decorador `@classmethod`"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": null,
+   "id": "0ee1c8d5",
+   "metadata": {},
+   "outputs": [],
+   "source": [
+    "class Estudiante:\n",
+    "    def __init__(self, nombre, ingreso):\n",
+    "        self.nombre = nombre\n",
+    "        self.ingreso = ingreso\n",
+    "\n",
+    "    @classmethod\n",
+    "    def desde_texto(cls, texto):\n",
+    "        nombre, ingreso = texto.split(\",\")\n",
+    "        return cls(nombre, int(ingreso))\n",
+    "\n",
+    "    def resumen(self):\n",
+    "        return f\"Estudiante(nombre={self.nombre}, ingreso={self.ingreso})\""
+   ]
+  }
+ ],
+ "metadata": {
+  "language_info": {
+   "name": "python"
+  }
+ },
+ "nbformat": 4,
+ "nbformat_minor": 5
+}
diff --git a/recursos/slides/01.qmd b/recursos/clases/01.qmd
similarity index 100%
rename from recursos/slides/01.qmd
rename to recursos/clases/01.qmd
diff --git a/recursos/slides/02_1.qmd b/recursos/clases/02_1.qmd
similarity index 100%
rename from recursos/slides/02_1.qmd
rename to recursos/clases/02_1.qmd
diff --git a/recursos/slides/02_2.qmd b/recursos/clases/02_2.qmd
similarity index 100%
rename from recursos/slides/02_2.qmd
rename to recursos/clases/02_2.qmd
diff --git a/recursos/clases/04.qmd b/recursos/clases/04.qmd
new file mode 100644
index 0000000..1760586
--- /dev/null
+++ b/recursos/clases/04.qmd
@@ -0,0 +1,13 @@
+---
+title: "Clase 4: Programación Orientada a Objetos"
+---
+
+{{< downloadthis ../../notebooks/clase_04.ipynb dname=clase_04 label="Descargar Notebook" icon=journal-code type=default class=data-button id=clase_04 >}}
+
+<iframe
+  src="https://tomicapretto.com/jupyter-lite-site/notebooks/?path=pp/clase_04.ipynb"
+  width="100%"
+  height="800"
+  style="border: 1px solid #ddd;">
+</iframe>
+