{
  description = "what does the cow say";

  inputs = {
    nixpkgs.url = "github:NixOS/nixpkgs";
  };

  outputs = { self, nixpkgs }: {

    devShells = {
      x86_64-linux.default =
        nixpkgs.legacyPackages.x86_64-linux.mkShell {
          packages = [
            nixpkgs.legacyPackages.x86_64-linux.cowsay
          ];
        }; # mkShell
    }; # devShells

  }; # outputs
}