In the dollar game, you draw a network of nodes. All the nodes have at least one connection, some multiple. You have a dollar value within each node, with some nodes negative and some positive. The games goal is to ensure every node has a minimum of zero dollars. You tap on a node to share its value with its neighbours. The share is the challenge since the node has to share its value with all the nodes directly connected to it—an app inspired by the excellent youtube channel Numberphile.