Rewrite the OCR instructions

exercises/ocr-numbers/instructions.md

@@ -1,65 +1,31 @@
 # Instructions
 
-Given a 3 x 4 grid of pipes, underscores, and spaces, determine which number is represented, or whether it is garbled.
+Optical Character Recognition or OCR is software that converts images of text into machine-readable text.
+Given a grid of characters representing some digits, convert the grid to a string of digits.
+If the grid has multiple rows of cells, the rows should be separated in the output with a `","`.
 
-## Step One
+- The grid is made of one of more lines of cells.
+- Each line of the grid is made of one or more cells.
+- Each cell is three columns wide and four rows high (3x4) and represents one digit.
+- Digits are drawn using pipes (`"|"`), underscores (`"_"`), and spaces (`" "`).
 
-To begin with, convert a simple binary font to a string containing 0 or 1.
+## Edge cases
 
-The binary font uses pipes and underscores, four rows high and three columns wide.
+- If the input is not a valid size, your program should indicate there is an error.
+- If the input is the correct size, but a cell is not recognizable, your program should output a `"?"` for that character.
 
-```text
-     _   #
-    | |  # zero.
-    |_|  #
-         # the fourth row is always blank
-```
-
-Is converted to "0"
-
-```text
-         #
-      |  # one.
-      |  #
-         # (blank fourth row)
-```
-
-Is converted to "1"
-
-If the input is the correct size, but not recognizable, your program should return '?'
-
-If the input is the incorrect size, your program should return an error.
-
-## Step Two
+## Examples
 
-Update your program to recognize multi-character binary strings, replacing garbled numbers with ?
-
-## Step Three
-
-Update your program to recognize all numbers 0 through 9, both individually and as part of a larger string.
-
-```text
- _
- _|
-|_
-
-```
-
-Is converted to "2"
+The following input (without the comments) is converted to `"1234567890"`.
 
 ```text
       _  _     _  _  _  _  _  _  #
-    | _| _||_||_ |_   ||_||_|| | # decimal numbers.
+    | _| _||_||_ |_   ||_||_|| | # Decimal numbers.
     ||_  _|  | _||_|  ||_| _||_| #
-                                 # fourth line is always blank
+                                 # The fourth line is always blank,
 ```
 
-Is converted to "1234567890"
-
-## Step Four
-
-Update your program to handle multiple numbers, one per line.
-When converting several lines, join the lines with commas.
+The following input is converted to `"123,456,789"`.
 
 ```text
     _  _
@@ -75,5 +41,3 @@ When converting several lines, join the lines with commas.
   ||_| _|
 
 ```
-
-Is converted to "123,456,789".