With a list of all three letter words in the English language I made a small booklet.
I was really interested in color-letter synesthesia (which means: when you read, you see the letters in different colors) so I did a small unofficial study among 30 people.

Every page of the booklet resembles a colour: pink, red, orange, yellow, green, blue, purple, brown, white, grey and black. Every letter of the alphabet has been cut up according to their percentages, e.g. if the testgroup said that the letter a is about 50% red (that means half of the testgroup thought the letter a was red), then on the red page you’ll see the letter a for just 50%.

Printed on semi-transparent neon yellow paper, all pages on top of each other make a full type again.