Dollar Shuffle is a simple game based on one explored in the Numberphile video The Dollar Game. It is written for the Godot game engine and is free and open source under the GPL-3 license.
To build Dollar Shuffle, download and install version 3.0.6 of the Godot Engine. Once Godot is opened, import the source code as a Godot project. Build the project for whatever platform you intend using the Export menu.