The scene
Municipal Aquarium · Jellyfish tankDuring an evening visit, the jellyfish appeared bathed in violet, a colour reserved for technical rehearsals. Someone had used their remote while the guide welcomed the visitors.
The log retains the starting colour, the final colour and a signal showing that the tank passed through green. The remotes cannot choose colours freely: each runs a fixed sequence of two buttons.
What we know for certain
One of these three people pressed their remote exactly once. Both steps ran in full and in order, with no other intervention. The controller works correctly. The colour changes follow the rules stated here; no knowledge of mixing coloured light is needed.
The three accounts
Abril Solé
Visitor experience technician«My remote presses A first, then B.»
Guillem Ferrer
Tank curator«Mine uses button A twice.»
Salma León
Maintenance technician«My remote presses B first, then A.»
Examine the evidence
0 of 5 openedOpening these five clues does not cost points.
01Button A's cycle
Each press of A advances one place around this closed cycle: blue, green, violet, blue. From violet, it returns to blue.
02Button B's rule
B swaps blue and violet. If the colour is green, it leaves it green. It does not automatically move on to any other colour.
03Before and after
The tank started blue and ended violet. The sensors at both moments were working, and the lights were never switched off.
04The intermediate signal
Between the start and the finish, green was recorded after the first step. That record refers to the actual colour of the tank, not the name of a button.
05The sealed remotes
Abril runs A-B; Guillem, A-A; Salma, B-A. The sequences were sealed, and nobody could alter them or stop them halfway.