diff --git a/.github/workflows/ci.yaml b/.github/workflows/ci.yaml
new file mode 100644
index 0000000..b554b25
--- /dev/null
+++ b/.github/workflows/ci.yaml
@@ -0,0 +1,47 @@
+jobs:
+  build:
+    runs-on: ubuntu-latest
+    steps:
+      - name: Native dependencies
+        run: sudo apt install libgmp-dev libgl1-mesa-dev libxcursor-dev libxi-dev libxinerama-dev libxrandr-dev libxxf86vm-dev
+      - uses: "actions/checkout@v3"
+      - id: setup-haskell-cabal
+        uses: "haskell/actions/setup@v2"
+        with:
+          cabal-version: "${{ matrix.cabal }}"
+          enable-stack: false
+          ghc-version: "${{ matrix.ghc }}"
+      - name: Update Hackage repository
+        run: cabal update
+      - name: cabal.project.local.ci
+        run: |
+          if [ -e cabal.project.local.ci ]; then
+            cp cabal.project.local.ci cabal.project.local
+          fi
+      - name: freeze
+        run: cabal freeze
+      - uses: "actions/cache@v3"
+        with:
+          key: "${{ runner.os }}-${{ matrix.ghc }}-cabal-${{ hashFiles('cabal.project.freeze') }}"
+          path: |
+            ${{ steps.setup-haskell-cabal.outputs.cabal-store }}
+            dist-newstyle
+      - name: Install dependencies
+        run: cabal build all --enable-tests --enable-benchmarks --only-dependencies
+      - name: build all
+        run: cabal build all --enable-tests --enable-benchmarks
+      - name: test all
+        run: cabal test all --enable-tests
+      - name: haddock all
+        run: cabal haddock all 
+    strategy:
+      matrix:
+        cabal:
+          - '3.4'
+        ghc:
+          - '9.0.2'
+          - '8.10.7'
+name: Haskell CI
+on:
+  - push
+  - pull_request
diff --git a/README.md b/README.md
index bf0e128..8a4d271 100644
--- a/README.md
+++ b/README.md
@@ -137,4 +137,4 @@ to use composable `Animation` wrapper similar to
 
 ### `demoLetterI` with smoothed normals
 
-[![smoothed demo letter](./img/i_smoothed_thumb.png)](https://raw.githubusercontent.com/sorki/implicitpipe/master/img/i_smoothed_thumb.png)
+[![smoothed demo letter](./img/i_smoothed_thumb.png)](https://raw.githubusercontent.com/sorki/implicitpipe/master/img/i_smoothed.png)
diff --git a/cabal.project.local.ci b/cabal.project.local.ci
new file mode 100644
index 0000000..7ad7366
--- /dev/null
+++ b/cabal.project.local.ci
@@ -0,0 +1,24 @@
+-- NOTE: having implicit listed here breaks hint
+-- see https://github.com/Haskell-Things/implicitpipe/issues/2
+-- but it is required for CI now
+-- until 0.4
+source-repository-package
+    type: git
+    location: https://github.com/Haskell-Things/ImplicitCAD
+    tag: ae794b901e9677593815fad741d87ff56846562d
+
+-- fork due to resizeBuffer PR https://github.com/tobbebex/GPipe-Core/pull/76
+source-repository-package
+    type: git
+    location: https://github.com/sorki/GPipe-Core
+    tag: 86a7b29014e7ebfb24ac17d5afcd877a38a1fbd5
+    subdir:
+      GPipe-Core
+
+-- until next release
+source-repository-package
+    type: git
+    location: https://github.com/plredmond/GPipe-GLFW
+    tag: 3d7e91a20a80fe31e910884b151ebe4d26e8274e
+    subdir:
+      GPipe-GLFW
diff --git a/ci.dhall b/ci.dhall
new file mode 100644
index 0000000..3593ec0
--- /dev/null
+++ b/ci.dhall
@@ -0,0 +1,18 @@
+let haskellCi =
+      https://raw.githubusercontent.com/sorki/github-actions-dhall/pending/haskell-ci.dhall
+
+in    haskellCi.generalCi
+        (   [ haskellCi.BuildStep.Name
+                { name = "Native dependencies"
+                , run =
+                    "sudo apt install libgmp-dev libgl1-mesa-dev libxcursor-dev libxi-dev libxinerama-dev libxrandr-dev libxxf86vm-dev"
+                }
+            ]
+          # haskellCi.matrixSteps
+        )
+        ( Some
+            { ghc = [ haskellCi.GHC.GHC902, haskellCi.GHC.GHC8107 ]
+            , cabal = [ haskellCi.Cabal.Cabal34 ]
+            }
+        )
+    : haskellCi.CI.Type
diff --git a/ci.sh b/ci.sh
new file mode 100755
index 0000000..7d7cc86
--- /dev/null
+++ b/ci.sh
@@ -0,0 +1,13 @@
+#!/usr/bin/env bash
+# Script by @fisx
+
+set -eo pipefail
+cd "$( dirname "${BASH_SOURCE[0]}" )"
+
+echo "regenerating .github/workflows/ci.yaml..."
+
+mkdir -p .github/workflows
+
+# based on https://github.com/vmchale/github-actions-dhall
+which dhall-to-yaml || cabal install dhall-yaml
+dhall-to-yaml --file ci.dhall > .github/workflows/ci.yaml
diff --git a/default.nix b/default.nix
index 968061e..d474d65 100644
--- a/default.nix
+++ b/default.nix
@@ -1,4 +1,11 @@
-{ pkgs ? import <nixpkgs> { overlays = [ (import ./overlay.nix) ]; }}:
+{ rev ? "c542baa0c894796c92a8173dead027f3b952c22e"
+, overlays ? [ (import ./overlay.nix) ]
+, pkgs ?
+    if ((rev == "") || (rev == "default") || (rev == "local"))
+      then import <nixpkgs> { inherit overlays; }
+      # Do not guard with hash, so the project is able to use current channels (rolling `rev`) of Nixpkgs
+      else import (builtins.fetchTarball "https://github.com/NixOS/nixpkgs/archive/${rev}.tar.gz") { inherit overlays; }
+}:
 
 let
   src = pkgs.nix-gitignore.gitignoreSource [ ] ./.;
diff --git a/example-haskell/SomeModule.hs b/example-haskell/SomeModule.hs
index 334973c..8784009 100644
--- a/example-haskell/SomeModule.hs
+++ b/example-haskell/SomeModule.hs
@@ -9,10 +9,10 @@ import SomeOtherModule
 res = 2
 
 obj = union $ [
-    cubeR 0 False (V3 20 20 14)
+    cube False (V3 20 20 14)
   , translate (V3 20 20 20) (sphere 15)
   , translate (V3 30 20 20) (sphere 5)
-  , translate (V3 0 0 25) (cubeR 2 False (pure 10))
+  , translate (V3 0 0 25) (withRounding 2 $ cube False (pure 10))
   , translate (V3 25 0 0) (cylinder2 10 4 10)
   , translate (V3 (-25) 0 0) obj'
   ]
diff --git a/overlay.nix b/overlay.nix
index d195c5d..106cfab 100644
--- a/overlay.nix
+++ b/overlay.nix
@@ -13,8 +13,8 @@ let
   gpipeGlfwSrc = super.fetchFromGitHub {
      owner = "plredmond";
      repo = "GPipe-GLFW";
-     rev = "83d26eb7b41d67f5ac6fbd1bd8758d72c660e039";
-     sha256 = "0fg60amvp2v37cwmvfa0n7if1ppisjjh3bknmrr17m7fbfbbxlhq";
+     rev = "3d7e91a20a80fe31e910884b151ebe4d26e8274e";
+     sha256 = "0rx00mxlz6jlipx19h271mbnp8l9kzgm3dhwprwww4gf8g43r7vd";
   };
 in
   ({
@@ -25,12 +25,12 @@ in
            GPipe = hsuper.callCabal2nix "GPipe" "${gpipeSrc}/GPipe-Core" {};
            GPipe-GLFW = hsuper.callCabal2nix "GPipe-GLFW" ("${gpipeGlfwSrc}/GPipe-GLFW") {};
 
-           # until > 3.0.2 is out
+           # until > 4.0.0 is out
            implicit = hsuper.callCabal2nix "implicit" (super.fetchFromGitHub {
-              owner = "colah";
+              owner = "Haskell-Things";
               repo = "ImplicitCAD";
-              rev = "8dff5531cdc4d9ed32bf958e3945b4a3a0ef3774";
-              sha256 = "0bp797a9wlpyw2d6b4csz5ikqq3wy1qry0iabl7r7axjrhvnfp56";
+              rev = "ae794b901e9677593815fad741d87ff56846562d";
+              sha256 = "0q8bj3jysgl7kfivrag8g6yx58n5rxf69qsc3lw43941lamaxpda";
            }) {};
         });
       });
diff --git a/src/Graphics/Implicit/Viewer/Loaders.hs b/src/Graphics/Implicit/Viewer/Loaders.hs
index efe2eb7..f935524 100644
--- a/src/Graphics/Implicit/Viewer/Loaders.hs
+++ b/src/Graphics/Implicit/Viewer/Loaders.hs
@@ -16,7 +16,6 @@ import Data.List (isSuffixOf)
 import Data.Time (getCurrentTime, diffUTCTime)
 import Data.Typeable (Typeable)
 
-import Linear (V3(V3))
 import Graphics.Implicit
 import Graphics.Implicit.Primitives (getBox)
 import Graphics.Implicit.ExtOpenScad.Definitions
diff --git a/stack.yaml b/stack.yaml
index d643536..3027352 100644
--- a/stack.yaml
+++ b/stack.yaml
@@ -2,7 +2,7 @@
 
 # Specifies the GHC version and set of packages available (e.g., lts-3.5, nightly-2015-09-21, ghc-7.10.2)
 
-resolver: lts-16.25
+resolver: lts-19.5
 
 # Local packages, usually specified by relative directory name
 packages:
@@ -10,19 +10,16 @@ packages:
 
 # Packages to be pulled from upstream that are not in the resolver (e.g., acme-missiles-0.3)
 extra-deps:
-- storable-endian-0.2.6
-- quickspec-2.1.5@sha256:1d1cc020fa9075cb5fafd4056fe1d930d5763b954fa8200e57ce6aba057544b2,3557
-- twee-lib-2.2@sha256:9fe9327505d8f450a94f2fc9eea74b292901b7992d520aa1dd4f0410fbe0e594,2112
 - git: git@github.com:sorki/GPipe-Core
   commit: 86a7b29014e7ebfb24ac17d5afcd877a38a1fbd5
   subdirs:
   - GPipe-Core
 - git: git@github.com:plredmond/GPipe-GLFW
-  commit: 83d26eb7b41d67f5ac6fbd1bd8758d72c660e039
+  commit: 3d7e91a20a80fe31e910884b151ebe4d26e8274e
   subdirs:
   - GPipe-GLFW
-- git: git@github.com:colah/ImplicitCAD
-  commit: 8dff5531cdc4d9ed32bf958e3945b4a3a0ef3774
+- git: git@github.com:Haskell-Things/ImplicitCAD
+  commit: ae794b901e9677593815fad741d87ff56846562d
 
 # Override default flag values for local packages and extra-deps
 flags: {}