[math-fun] Hackenbush applet?

Does anyone know of a browser applet or smartphone app that lets a human play Red-Blue Hackenbush against a computer? One nice way to convince people that a certain Hackenbush position H has value 1/2 would to give them a chance to play the game consisting of m copies of H plus n copies of a game with value -1, for various values of m and n, sometimes playing Red and sometimes playing Blue. Jim Propp