Colourblind-friendly keys and doors

[cxong]

For some kinds of colourblindness, the colour-coded keys and doors can be impossible to distinguish. Instead, there should be additional visual cues differentiating the different keys and doors.

• Use shape - for the keys, we could have keys with different numbers of bits - 1, 2, 3, 4
• For doors, there needs to be different markings, on the top but preferably also on the front

[cxong]

Normal:

Protanopia:

Deuteranopia:

Tritanopia: