Bertie the Brain (en.wikipedia.org)

In August 1950 Toronto engineer Josef Kates unveiled "Bertie the Brain," a four-metre exhibition computer that let fairgoers play tic-tac-toe against an electronic opponent. Built to showcase Kates’s additron tube (a compact vacuum-tube full-adder), the machine accepted moves on a nine-button keypad and displayed Xs and Os with large lights on a vertical grid. It had adjustable difficulty, responded almost instantly, and at the highest setting was programmed to be unbeatable. After two weeks at the Canadian National Exhibition the Rogers Majestic-built device was dismantled and largely forgotten, though it drew big crowds and press attention at the time. Bertie matters to the AI/ML and computing communities as an early, public demonstration of computerized gameplay and real-time decision logic — arguably one of the first computer-based games with any visual display, predating screen-based titles like OXO. Technically it packaged logic around Kates’s additron tube rather than transistors; patent delays and the rapid rise of transistors prevented wider adoption of the tube or further development of similar machines. Today Bertie is a historical touchstone for interactive computing and early AI demonstrations: a specialized solver for a simple game that showcased real-time automated play long before mainstream digital graphics and general-purpose game software emerged.