diff --git a/.gitignore b/.gitignore
index 5099aff..3bd18d9 100644
--- a/.gitignore
+++ b/.gitignore
@@ -1,9 +1,7 @@
 *.png
-*.json
 *.svg
 !pool/**/*.svg
-!pool/**/*.png
-!pool/**/*.json
+!images/**/*.png
 
 .idea
 
diff --git a/Cargo.toml b/Cargo.toml
index 5994e77..48d30dc 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -4,8 +4,9 @@ version = "1.0.0"
 authors = ["Ingolf Wagner <contact@ingolf-wagner.de>"]
 edition = "2018"
 
+
 # See more keys and their definitions at https://doc.rust-lang.org/cargo/reference/manifest.html
-description = "Convenience library to use geo polygons to create art."
+description = "Convenience library to use geo to create art."
 documentation = "https://github.com/mrVanDalo/polygon-art"
 homepage = "https://github.com/mrVanDalo/polygon-art"
 repository = "https://github.com/mrVanDalo/polygon-art"
diff --git a/README.md b/README.md
index 0586494..df8f8cb 100644
--- a/README.md
+++ b/README.md
@@ -1,12 +1,22 @@
-Convenience library to create art using [geo](https://georust.org/)
-polygons.
+Convenience library to create art using [geo](https://georust.org/).
 
 * Creates CLI interface (including random seed management)
 * renders SVGs and PNG
-* comes with helper functions, to make live more convenient.
+* comes with helper functions and extensions, to make live more convenient.
     * load SVGs
     * scaling
 
+# Asteroids
+
+asteroids is an example binary which renders an
+image inspired by the
+[asteroids game from the 1979](https://de.wikipedia.org/wiki/Asteroids).
+
+![image](./images/asteroids.png)
+
+run `asteroids --help` to get information.
+All binaries created by polygon art have the same
+command line interface.
 
 # How to run examples
 
diff --git a/default.nix b/default.nix
deleted file mode 100644
index 8dce5bb..0000000
--- a/default.nix
+++ /dev/null
@@ -1,27 +0,0 @@
-{ rustPlatform, fetchgit, stdenv, cairo, ... }:
-
-rustPlatform.buildRustPackage rec {
-  name = "image-geneartor-${version}";
-  version = "3.0.0";
-  # src = ./.;
-  src = fetchgit{
-    url = "https://github.com/mrVanDalo/image-generator";
-    rev = "f8c1bf958aeea1808df6baea62eeb2949aa5fe65";
-    sha256 = "1swa2i57sdag3zapzx3m9mdarci0xfjczr611320zampw505ai09";
-  };
-
-  cargoSha256 = "07pwds279qc54g5fza805ah2m8jhrdzng7vb1bi24a9ra9ci8s29";
-  verifyCargoDeps = true;
-
-  buildInputs = [ cairo ];
-
-  meta = with stdenv.lib; {
-    description =
-      "An image generator unsing entropy and a JSON as configuration.";
-    homepage = "https://github.com/mrVanDalo/image-generator";
-    license = licenses.gplv3;
-    maintainers = [ maintainers.mrVanDalo ];
-    platforms = platforms.all;
-  };
-}
-
diff --git a/images/asteroids.png b/images/asteroids.png
new file mode 100644
index 0000000..43cd6a7
Binary files /dev/null and b/images/asteroids.png differ