Sequence Lock

This lock is a sequence detector, a little state machine. Press the secret symbol for the current state and the token steps forward; press a wrong one and it snaps all the way back to Start. Read the token, remember what failed, re-enter the part you already know, and reach the 🔓 in as few presses as you can.

What you're actually learning

A sequence detector is one of the most common state machines in digital design. Each state remembers how much of a target pattern you have matched so far: the right input advances it, a wrong input drops it back. Real detectors also handle overlap, where a wrong symbol can still be a partial match; this one keeps it simple and resets to Start. Build one for real in the state machines lesson.

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