Wall Colour Clock

About

• Creator's page: [1]
• Forum thread

Usage

All that you really have to remember is:

• The sequence in time is Red, Green, Yellow, Blue;
• That all four of these colours may appear in the top row, but only the first three may appear on the bottom (there is one all-blue test pattern, but that's done by setting a specific invalid time);
• The left-most pair code the hour and the right-most pair code the minutes, with a five minute resolution.

Some easy times to remember?

• 12:00 (noon or midnight) is all red;
• 4:20 is all green (lol);
• 8:40 is all yellow;
• 9:45 is both columns with blue on top and red on the bottom.

To get you thinking about the combinations:

• how many possible combinations are there? (Hint: a gross answer!)
• how many combinations with only one colour showing? (Hint: see above)
• how many times which only use at least one red and at least one green colour and no other colours are there (the Christmas combinations)? (no hints!)