Every chip in every computer is built from tiny switches. Wire them into logic gates, gates into adders and memory, and work your way up to a processor. Each circuit you solve becomes a part you can use in the next.
Wire (W): drag to draw. Wires only connect where you draw them, so wires side by side stay separate. Drag into a part's pin to connect it. Drag straight across another wire to make a crossing (the wires pass over each other); stop on it to make a junction.
Bus (B): an 8-bit wire carrying a whole number.
Parts: pick one and click to place. R rotates. Select (V) moves parts, and double-click a Number to change it.
Erase (E) or right-drag removes wires and parts. Ctrl+Z undoes.
Click the switches on the left to test your circuit live: lit copper is ON. Press Test (T) to check it against every case. Fewer transistors earn more stars.
Pan with the middle mouse button or Space + drag; zoom with the wheel.