Three in a Row: read the opponent

Three in a Row builds a readable opponent in ten Sinclair BASIC lessons. Eight runnable programs grow from a numbered board through two-player rules to a computer that wins, blocks and explains its choices.

A worked fork exposes the limits of looking one move ahead. Finish with a session tally, alternating starters and a self-starting tape. The game uses a stock 48K ZX Spectrum, with no timer or sound to hurry your decisions.