A simple fidget toy with differential gears.

Print 4 gears and one axes. Then snap them together and have fun.

Built with OnShape. Get the model here: https://cad.onshape.com/documents/c4e0bdeedeab753ff366c2b5/w/b918b9353a3d6edec991b3d8/e/3d61770d72b02bb5ac6e1588?renderMode=0&uiState=62be0c3dbc9190096b542222