Braille

Braille is an alphabet designed to be read by touch rather than sight. A “letter” in Braille is represented by a matrix of dots 2 wide and 3 high. Braille is typically written by embossing paper or another material to create some combination of bumps in this 2x3 pattern. This makes it possible to interpret the letters by feeling the bumps with a finger pad.

One way to force players to read a Braille message without looking at it is to paste the embossed Braille inside of a closed box with a hole. To read the message, players must reach a hand in through the hole and feel for the message.

Although not the original point, Braille messages can also be read visually. To make this more challenging, hide the Braille letters in objects or images that naturally have grids. Here is an example of hiding a Braille message in the windows of a skyline.

The image looks like ordinary drawing of buildings. But a closer look reveals that all the windows are grouped in 2x3 grids like Braille letters are. The lit windows encode in each of these grids a Braille letter, spelling out “I Spy”.