Piano
DraftSeven keys, a Braille octave number and one coloured light. Together they pick a four-note sequence from the manual.
First appears in level 9
How to recognise it
A short keyboard with seven keys labelled C, D, E, F, G, A, B from left to right. Braille dots on the keys encode an octave number from 1 to 7 (the same number on every key). One light next to the keys glows red, yellow, green or blue. The keys play a note when pressed, but the sound is not needed to solve the module.
Procedure
Feel the Braille on the keys and say the octave number: "octave three". Then wait for four notes or four key positions. The keys count from the left: C is 1, D is 2, E is 3, F is 4, G is 5, A is 6, B is 7. Play them in the order given, repeats included, and say each one as you press it.
Common mistakes
Calling octave and colour separately. One clue alone still leaves four or seven possible sequences.
Dropping the fourth note or a repeated note. "C C G G" has four presses, not two.
Playing while the sequence is still being called. Wait for all four, repeat them back, then play.
After a Chaos interruption, guessing where you stopped. Start the sequence again from note one.
Solver
Enter what you see on the bomb and get the action for the current state.