Last holiday season, we received a puzzling treat from our friends at Pentagram: Decipher, a small olive green book of 14 cryptograms. Designed by Pentagram partner Harry Pearce and Jason Ching, the book contains a series of codes -- here a page of numbered polygons, there a thicket of seemingly nonsensical text -- each with a cryptic clue (e.g., "Just in the nick of time."). Thwarted as we were to convey the book's contents in a blog post, we were thrilled to hear from Michael Bierut that after five months of work, Decipher is now available online "for hours of play at home." We'll get you started with the below Penta/cryptogram. The clue is "Midday nap," and we've posted the solution after the jump.

Answer: Replace the missing letters to spell FORTY WINKS.