The board beeps its way through POST and you have to beep it back. Four tones, one more added every round, and no second chances once you lose the thread.
Simon, with a POST speaker instead of coloured lights. Every pad has its own tone and its own waveform, so the sequence is something you can hear as well as watch.
The board plays a sequence. When the speaker goes quiet the pads unlock and you tap it back in order. Get it right and a new beep is added to the end.
One beep added per roundEvery few rounds the gap between beeps shortens. By round twelve it is coming at you fast enough that you stop counting and start going on rhythm.
Three speed stepsMiss a tone and the board posts an error code and the run ends. Strict mode off gives you one retry of the same sequence instead.
Strict can be turned offEach pad flashes and shows its own waveform, so the whole game is playable silently. Handy for playing it somewhere you should not be playing it.
Fully visual fallbackThe four pads are named after the POST codes a desktop actually gives you. If a machine of yours beeps one of these at you, it is telling you what is wrong before Windows ever loads.
Beep codes are the board telling you exactly where it stopped. Bring it in and it is usually a quick diagnosis rather than a long one.