One-Fold Silhouette Font
by Erik Demaine and Martin Demaine, 2018
This typeface splits each digit and letter of the alphabet into two possibly overlapping halves. Each half does not look like the original digit or letter (though it often looks like an L or F), obscuring the encoded message. But overlaying the halves on top of each other reveals the letter. The Folded Font shows the original font design.
In the Unfolded Font, the two halves are put on opposite sides of a transparent sheet, with the right half reflected. Click Fold/Unfold to fold along the central crease, revealing the text. Click Fold/Unfold again to unfold back to the puzzle state. Can you read the text without folding?
The Shadow Font gives you a preview of what you'll see after folding, but still lets you play with the Fold/Unfold button.
This typeface is inspired by silhouette puzzles such as the 1900-era “Question du Lapin” or “Rabbit Silhouette Puzzle”, where five cards stack up to form the silhouette of a rabbit, or the modern Kaboozle puzzle. In 2012, Asano, Demaine, Demaine, and Uehara proved that such puzzles are NP-complete, even when the stacking is implemented by folding (as in this typeface).