diff --git a/.envrc b/.envrc
new file mode 100644
index 0000000..21282b0
--- /dev/null
+++ b/.envrc
@@ -0,0 +1,3 @@
+#!/usr/bin/env bash
+
+use flake
\ No newline at end of file
diff --git a/.gitignore b/.gitignore
index cce9137..73b0670 100644
--- a/.gitignore
+++ b/.gitignore
@@ -26,5 +26,6 @@ cabal.project.local~
 # ignore vscodium's local config
 .vscode/
 
-# ignore nix result symlinks
-result*
\ No newline at end of file
+# ignore nix build system
+result*
+.direnv
\ No newline at end of file
diff --git a/Graphics/Engine.hs b/Graphics/Engine.hs
index 5416a90..3ddab38 100644
--- a/Graphics/Engine.hs
+++ b/Graphics/Engine.hs
@@ -44,15 +44,15 @@ processEvent = event noEvent $ \case
   EventMotion {} -> noEvent
   EventResize size -> Event $ Resize size
 
-run :: forall f. DisplayableSpace f => f Bool -> SF InputEvent Picture
-run st =
+run :: DisplayableSpace f => (Int, Int) -> f Bool -> SF InputEvent Picture
+run size st =
   let initSpace = gol' standardRule st
    in proc inp -> do
         let cmdev = processEvent inp
 
         playing <- accumHoldBy (const . not) True -< filterE isPlayPause cmdev
         time <- accum 0.2 -< mapFilterE getChangeSpeed cmdev
-        windowSize <- hold (100, 100) -< mapFilterE getResize cmdev
+        windowSize <- hold size -< mapFilterE getResize cmdev
 
         tick <- tickSignal -< time
         space <- engine initSpace -< gate tick playing
diff --git a/Main.hs b/Main.hs
index b13cd4c..5c166dc 100644
--- a/Main.hs
+++ b/Main.hs
@@ -6,6 +6,7 @@ import Graphics.Engine (initialSpace, run)
 import Graphics.Gloss
 import Graphics.GlossUtils (playYampa)
 
+-- random space just to test things
 space :: ToroidalSpace Bool
 space = tabulate (\(x, y) -> (x + y `mod` 5) * 10 + x - y > 30)
 
@@ -15,4 +16,4 @@ main =
     (InWindow "Conway's Game of Life" (200, 200) (10, 10))
     black
     30
-    (run space)
\ No newline at end of file
+    (run (200, 200) space)
diff --git a/flake.lock b/flake.lock
index e15f5a8..b1039cb 100644
--- a/flake.lock
+++ b/flake.lock
@@ -1,21 +1,5 @@
 {
   "nodes": {
-    "flake-compat": {
-      "flake": false,
-      "locked": {
-        "lastModified": 1627913399,
-        "narHash": "sha256-hY8g6H2KFL8ownSiFeMOjwPC8P0ueXpCVEbxgda3pko=",
-        "owner": "edolstra",
-        "repo": "flake-compat",
-        "rev": "12c64ca55c1014cdc1b16ed5a804aa8576601ff2",
-        "type": "github"
-      },
-      "original": {
-        "owner": "edolstra",
-        "repo": "flake-compat",
-        "type": "github"
-      }
-    },
     "flake-utils": {
       "locked": {
         "lastModified": 1638122382,
@@ -48,7 +32,6 @@
     },
     "root": {
       "inputs": {
-        "flake-compat": "flake-compat",
         "flake-utils": "flake-utils",
         "nixpkgs": "nixpkgs"
       }
diff --git a/flake.nix b/flake.nix
index 9b0d69c..d57e1bb 100644
--- a/flake.nix
+++ b/flake.nix
@@ -1,59 +1,54 @@
-# SPDX-FileCopyrightText: 2021 Serokell <https://serokell.io/>
-#
-# SPDX-License-Identifier: CC0-1.0
-
 {
-  description = "My haskell application";
+  description = "Conway's Game of Life in Haskell";
 
   inputs = {
     nixpkgs.url = "github:NixOS/nixpkgs";
     flake-utils.url = "github:numtide/flake-utils";
-
-    flake-compat.url = "github:edolstra/flake-compat";
-    flake-compat.flake = false;
   };
 
   outputs = { self, nixpkgs, flake-utils, ... }:
     flake-utils.lib.eachDefaultSystem (system:
       let
+        overlays = [ ];
         pkgs = nixpkgs.legacyPackages.${system};
-
-        haskellPackages = pkgs.haskellPackages;
-
-        jailbreakUnbreak = pkg:
-          pkgs.haskell.lib.doJailbreak (pkg.overrideAttrs (_: { meta = { }; }));
-
-        packageName = "conways-game-of-life";
-
         execName = "gol";
-      in {
-        packages.${packageName} =
-          haskellPackages.callCabal2nix packageName self rec {
-            # Dependency overrides go here
+        hp = pkgs.haskellPackages; # pkgs.haskell.packages.ghc921;
+        project = returnShellEnv:
+          hp.developPackage {
+            inherit returnShellEnv;
+            name = "conways-game-of-life";
+            root = ./.;
+            withHoogle = false;
+            overrides = self: super: with pkgs.haskell.lib; {
+              # Use callCabal2nix to override Haskell dependencies here
+              # cf. https://tek.brick.do/K3VXJd8mEKO7
+              # Example: 
+              # > NanoID = self.callCabal2nix "NanoID" inputs.NanoID { };
+              # Assumes that you have the 'NanoID' flake input defined.
+            };
+            modifier = drv:
+              pkgs.haskell.lib.addBuildTools drv (with hp; [
+                # Specify your build/dev dependencies here. 
+                hlint
+                haskell-language-server
+                ormolu
+
+                pkgs.mesa
+                pkgs.mesa_glu
+                pkgs.freeglut
+              ]);
           };
+      in
+      {
+        # Used by `nix build` & `nix run` (prod exe)
+        defaultPackage = project false;
 
-        defaultPackage = self.packages.${system}.${packageName};
-
-        apps.${execName} = {
+        defaultApp = {
           type = "app";
-          program = "${self.packages.${system}.${packageName}}/bin/${execName}";
+          program = "${self.defaultPackage.${system}}/bin/${execName}";
         };
 
-        defaultApp = self.apps.${system}.${execName};
-
-        devShell = pkgs.mkShell {
-          buildInputs = with haskellPackages; [
-            ghcid
-            cabal-install
-            hlint
-            pkgs.haskell-language-server
-            pkgs.ormolu
-
-            pkgs.mesa
-            pkgs.mesa_glu
-            pkgs.freeglut
-          ];
-          inputsFrom = builtins.attrValues self.packages.${system};
-        };
+        # Used by `nix develop` (dev shell)
+        devShell = project true;
       });
-}
\ No newline at end of file
+}
diff --git a/shell.nix b/shell.nix
deleted file mode 100644
index 81e3286..0000000
--- a/shell.nix
+++ /dev/null
@@ -1,8 +0,0 @@
-(import (
-  let lock = builtins.fromJSON (builtins.readFile ./flake.lock);
-  in
-  fetchTarball {
-    url = "https://github.com/edolstra/flake-compat/archive/${lock.nodes.flake-compat.locked.rev}.tar.gz";
-    sha256 = lock.nodes.flake-compat.locked.narHash;
-  }
-) { src = ./.; }).shellNix
\ No newline at end of file