March 27, 2026
Nine squares, 2,458 shocks
Fets and Crosses: Tic-Tac-Toe built from 2458 discrete transistors
2,458-transistor Tic-Tac-Toe ignites retro pride vs. “too many parts” skeptics
TLDR: A maker built a Tic-Tac-Toe machine from 2,458 individual transistors that plays perfectly, switching between memory and all-transistor logic. Commenters split between vintage admiration and optimization nagging—comparing it to the Intel 4004, calling it art, and asking if modern tools could cut the parts count.
Someone just built a full Tic-Tac-Toe computer out of 2,458 tiny switches called transistors—no microchip brain, just raw parts—and the internet is torn between awe and “why tho?” The creator hand-assembled two circuit boards, added a simple timer chip for the clock, survived three revisions (and a dropped board!), and ended up with a machine that plays perfectly, validates moves, and even swaps between a memory-based brain and a transistor-only brain.
Commenters lit up. One immediately compared the part count to the first commercial microprocessor, the Intel 4004, turning the thread into a retro flex fest. Others went full nostalgia—one user called it a “work of art” and begged for more hardware builds in a “sea of AI posts.” Meanwhile, the efficiency squad marched in: some argued modern tools could trim the logic, asking if hardware design software (HDL, a way to describe circuits in code) would’ve optimized it. Another voice asked the question everyone’s thinking: isn’t 2,458… a lot?
Then came the curveball: a link to MENACE—a 1960s Tic-Tac-Toe “computer” made of matchboxes—fueling jokes about trading silicon for shoeboxes. Verdict: equal parts engineering poetry and glorious overkill, with comments as spicy as the soldering iron.
Key Points
- •A complete Tic-Tac-Toe system was built from 2,458 discrete transistors with player-vs-player and player-vs-computer modes.
- •The first engine used an 18-bit ROM lookup table but was replaced by a purely combinational logic design capable of perfect play.
- •The design uses 19 flip-flops (18 for board state, 1 for active player) and a small set of gates.
- •Two-layer PCBs were designed in KiCad using hierarchical cells and replicate-layout techniques, with Manhattan routing (top vertical, bottom horizontal).
- •After three hand-assembled revisions and issues with PCB warpage, five engine and main boards were professionally assembled; a gameplay demo confirms operation.