{
  inputs = {
    nixpkgs.url = "github:NixOS/nixpkgs/nixos-unstable";
    kittysay.url = "github:uncenter/kittysay";
  };

  outputs = { self, nixpkgs, kittysay }: {
    nixosConfigurations.example = nixpkgs.lib.nixosSystem {
      system = "x86_64-linux";
      modules = [{
        environment.systemPackages = [
          inputs.kittysay.packages.${pkgs.system}.default
        ];
      }];
    };
  }
}