diff --git a/apps/default.nix b/apps/default.nix
index d36ec12..3b29289 100644
--- a/apps/default.nix
+++ b/apps/default.nix
@@ -11,4 +11,5 @@ in forAllSystems(system: let
     
     example = blib.mkApp { drv = bpkgs.example; name = "hello-nix"; };
    
+    netgen = blib.mkApp { drv = bpkgs.netgen; };
 })
diff --git a/devShells/default.nix b/devShells/default.nix
new file mode 100644
index 0000000..95d9645
--- /dev/null
+++ b/devShells/default.nix
@@ -0,0 +1,13 @@
+{ self, nixpkgs, ... }:
+let 
+    forAllSystems = nixpkgs.lib.genAttrs [ "x86_64-linux" ];
+    nixpkgsFor = forAllSystems (system: import nixpkgs { inherit system; });
+
+in forAllSystems(system: let 
+        pkgs = nixpkgsFor.${system};
+        bpkgs = self.packages.${system};
+        blib = self.lib;
+    in {
+    
+    netgen = import ./netgen.nix { inherit pkgs bpkgs; };
+})
diff --git a/devShells/netgen.nix b/devShells/netgen.nix
new file mode 100644
index 0000000..32b7cea
--- /dev/null
+++ b/devShells/netgen.nix
@@ -0,0 +1,15 @@
+{ pkgs, bpkgs, ... }:
+let 
+    python = pkgs.python3.withPackages(ps: []);
+
+in pkgs.mkShellNoCC {
+    packages = with pkgs; [
+        bpkgs.netgen
+        python
+    ];
+
+    shellHook = ''
+        export PYTHONPATH="${python}/${python.sitePackages}"
+        export PYTHONPATH="$PYTHONPATH:${bpkgs.netgen}/${python.sitePackages}"
+    '';
+}
diff --git a/flake.nix b/flake.nix
index 7ad5ef8..3051e25 100644
--- a/flake.nix
+++ b/flake.nix
@@ -36,5 +36,7 @@
         packages = import ./packages { inherit self nixpkgs; };
 
         apps = import ./apps { inherit self nixpkgs; };
+
+        devShells = import ./devShells { inherit self nixpkgs; };
     };
 }
diff --git a/packages/default.nix b/packages/default.nix
index 371fc35..5528fdd 100644
--- a/packages/default.nix
+++ b/packages/default.nix
@@ -6,5 +6,7 @@ let
 in forAllSystems(system: let pkgs = nixpkgsFor.${system}; in {
     
     example = pkgs.callPackage ./example {};
+
+    netgen = pkgs.callPackage ./netgen {};
    
 })
diff --git a/packages/example/flake.lock b/packages/example/flake.lock
deleted file mode 100644
index 1b0c91e..0000000
--- a/packages/example/flake.lock
+++ /dev/null
@@ -1,27 +0,0 @@
-{
-  "nodes": {
-    "nixpkgs": {
-      "locked": {
-        "lastModified": 1694422566,
-        "narHash": "sha256-lHJ+A9esOz9vln/3CJG23FV6Wd2OoOFbDeEs4cMGMqc=",
-        "owner": "NixOS",
-        "repo": "nixpkgs",
-        "rev": "3a2786eea085f040a66ecde1bc3ddc7099f6dbeb",
-        "type": "github"
-      },
-      "original": {
-        "owner": "NixOS",
-        "ref": "nixos-unstable",
-        "repo": "nixpkgs",
-        "type": "github"
-      }
-    },
-    "root": {
-      "inputs": {
-        "nixpkgs": "nixpkgs"
-      }
-    }
-  },
-  "root": "root",
-  "version": 7
-}
diff --git a/packages/example/flake.old.nix b/packages/example/flake.old.nix
deleted file mode 100644
index 2e3f818..0000000
--- a/packages/example/flake.old.nix
+++ /dev/null
@@ -1,71 +0,0 @@
-{
-    description = "Example with hello nix.";
-    nixConfig.bash-prompt = "\[nix-develop\]$ ";
-
-    inputs = {
-        nixpkgs.url = "github:NixOS/nixpkgs/nixos-unstable";
-    };
-
-    outputs = { self, nixpkgs, ... }:
-    let
-        systems = [ "x86_64-linux" ];
-        forAllSystems = nixpkgs.lib.genAttrs systems;
-        nixpkgsFor = forAllSystems (system: import nixpkgs { inherit system; });
-
-    in {
-        packages = forAllSystems (system: {
-            example = let
-                pkgs = nixpkgsFor.${system};
-                pname = "example";
-                version = "1.0";
-
-            in pkgs.stdenv.mkDerivation {
-                inherit pname version;
-
-                # local source
-                src = ./.;
-
-                nativeBuildInputs = with pkgs; [ cmake ninja ];
-
-                meta = with pkgs.lib; {
-                    homepage = "https://www.example.org/";
-                    description = "Example with hello nix.";
-                    license = licenses.cc0;
-                    platforms = platforms.linux;
-                    maintainers = [];
-                    broken = false;
-                };
-            };
-
-            default = self.packages.${system}.example;
-        });
-
-        devShells = forAllSystems (system: {
-            example = let
-                pkgs = nixpkgsFor.${system};
-                example = self.packages.${system}.example;
-
-            in pkgs.mkShellNoCC {
-                packages = [
-                    example
-                ];
-            };
-
-            default = self.devShells.${system}.example;
-        });
-
-        apps = forAllSystems (system: {
-            example = let
-                pkgs = nixpkgsFor.${system};
-                example = self.packages.${system}.example;
-
-            in {
-                type = "app";
-                program = "${example}/bin/hello-nix";
-            };
-
-            default = self.apps.${system}.example;
-        });
-
-    };
-}
diff --git a/packages/netgen/default.nix b/packages/netgen/default.nix
new file mode 100644
index 0000000..406d008
--- /dev/null
+++ b/packages/netgen/default.nix
@@ -0,0 +1,63 @@
+{ 
+    stdenv, lib, pkgs,
+    version ? "6.2.2304",
+    sha256 ? "sha256-Rd7G316oIDklVq4uo7pS+v9ZqL+oV+RtZVU6iKYJCjM=", ...
+}:
+stdenv.mkDerivation {
+    pname = "netgen";
+    inherit version;
+
+    src = pkgs.fetchFromGitHub {
+        owner = "NGSolve";
+        repo = "netgen";
+        rev = "v${version}";
+        sha256 = sha256;
+    };
+
+    patches = [
+        ./regex-version.patch
+    ];
+
+    cmakeFlags = [
+        "-G Ninja"
+        "-D CMAKE_BUILD_TYPE=Release"
+        "-D USE_NATIVE_ARCH:BOOL=OFF"
+        "-D USE_OCC:BOOL=ON"
+        "-D USE_PYTHON:BOOL=ON"
+        "-D USE_GUI:BOOL=ON"
+        "-D USE_MPI:BOOL=ON"
+        "-D USE_SUPERBUILD:BOOL=OFF"
+        "-D PREFER_SYSTEM_PYBIND11:BOOL=ON"
+    ];
+
+    nativeBuildInputs = with pkgs; [
+        cmake
+        ninja
+        git
+        (python3.withPackages (ps: with ps; [
+            pybind11
+            mpi4py
+        ]))
+    ];
+
+    buildInputs = with pkgs; [
+        zlib
+        tcl
+        tk
+        mpi
+        opencascade-occt
+        libGL
+        libGLU
+        xorg.libXmu
+        metis
+    ];
+
+    meta = with pkgs.lib; {
+        homepage = "https://github.com/NGSolve/netgen";
+        description = "NETGEN is an automatic 3d tetrahedral mesh generator";
+        license = licenses.lgpl21Only;
+        platforms = platforms.linux;
+        maintainers = [];
+        broken = pkgs.stdenv.isDarwin;
+    };
+}
diff --git a/packages/netgen/regex-version.patch b/packages/netgen/regex-version.patch
new file mode 100644
index 0000000..16330c2
--- /dev/null
+++ b/packages/netgen/regex-version.patch
@@ -0,0 +1,11 @@
+--- a/cmake/generate_version_file.cmake
++++ b/cmake/generate_version_file.cmake
+@@ -39,7 +39,7 @@ string(REGEX REPLACE "^v[0-9]+\\.[0-9]+\\.[0-9]+\\-[0-9]+\\-([0-9a-z]+).*" "\\1"
+ set(NETGEN_VERSION_SHORT ${NETGEN_VERSION_MAJOR}.${NETGEN_VERSION_MINOR}.${NETGEN_VERSION_PATCH})
+ set(NETGEN_VERSION_LONG ${NETGEN_VERSION_SHORT}-${NETGEN_VERSION_TWEAK}-${NETGEN_VERSION_HASH})
+ 
+-if(NETGEN_VERSION_TWEAK)
++if(NETGEN_VERSION_TWEAK AND NOT NETGEN_VERSION_TWEAK STREQUAL git_version_string)
+   # no release version - nightly build
+   set(NETGEN_VERSION ${NETGEN_VERSION_LONG})
+ else()