Picaxe 08M robot plays Tic-Tac-Toe . It always wins or ties if it goes first and it always goes first . The play algorithm is based on an article in the 1971 Radio Electronics magazine by Don Lancaster called Tic-Tac-Tronix . It uses 253 of the 08m's 256 available program bytes . Due to the limited memory and I/O pins , the end of the game is signaled by closing the gripper in the home position . The code and schematic are available at letsmakerobots.com .