"Not in the bed. Must have slid down. He stooped and lifted the valance. The book, fallen, sprawled against the bulge of the orangekeyed" (U4.328)
The (Greek) key is a geometrical pattern used by Ancient Greeks in carvings and on pottery. There are many variations on it. You can see a simple Greek key on the scarf of the woman in this PC, and on the head band of the famous Charioteer statue in Delphi. Although its meaning is unknown, it has been postulated that the Greek key may be connected to the labyrinth where Theseus fought the Minotaur.