Enter in a long number (e.g. 8929834782937489) and it will create a ring of segments of colours corresponding to the digits you input. Try... 0101010444555444010101044455544401010104445554440101010444555444 for a neat example pattern. Hold 'z' key just after entering in the number to make the colours more contrasting for numbers with digits close to each other (e.g. 01010101 will have opposite colours instead).
You can use it to show your phone number to people by screenshotting this, and have them have to work out the number from the picture.