Wire up a working logic circuit using a single building block, the humble NAND gate, and prove it matches the spec.
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How to play
Each level hands you a set of inputs and a target Boolean specification. Your job is to assemble a circuit that produces the correct output for every possible combination of inputs, using only NAND gates.
Press Add NAND, then click two source nodes (an input or an existing gate) to wire its two inputs.
Choose which node is the circuit's output with Set as Output.
A live truth-table harness checks your circuit against the target, row by row, match every row to win.
You're scored on gate count against the level's par, so the tighter your build, the better.
Controls
Desktop: click Add NAND, then click nodes to wire them; click a node and Set as Output; Hint auto-builds a step.
Phone & tablet: tap the same buttons and tap nodes to wire, fully touch-friendly.
Tips & strategy
Remember a NAND is just an inverted AND, feeding the same node into both inputs gives you a NOT.
Reuse existing gates as shared inputs to stay under par instead of rebuilding sub-expressions.
Watch the truth table as you wire; chase the rows that are still mismatched.
What you'll learn
Truthgate turns digital logic design into a build-and-verify puzzle, showing how every gate can be built from NAND.
Skills: digital logic, logic gates, functional completeness, circuit design
Best for: roughly grades 9–12 (ages 14+)
For parents & teachers: digital logic from NAND alone.
About Truthgate
Truthgate turns digital logic design into a build-and-verify puzzle: NAND is functionally complete, so every Boolean function can be made from it alone. It's an original, free browser game with a date-seeded daily level and an endless practice campaign.
A free, original browser game on PlayPendium. No download, no install.
