Quoted By:
I have to go, but I will leave an explanation first, in case anyone wants it.
Each color is the mechanism of a password digit, the two blocks with torches are meant to preserve the value (on/off) when you press the button, and each digit enables the one that is next to it. The first digit is the green (9th button in the panel), and for example if you press the button to the grey blocks before enabling the green, the system is restarted by giving current to the wire in the middle of the system and every button value becomes off (thats what the third block is for, its a compacted logical door). Only when the last digit (blue) is enabled, the door is opened. There is no need to check with a door if the other digits are enabled too, because if you enable the last digit before enabling the previous one, the system is restarted, and so on, so you have to press all the corresponding buttons.