The Flight to Lucifer by Harold Bloom

Perscors studied the more curious features of his boat. A lance decorated with a ladder-like tree pattern rose from its precise middle, below the mast. Perscors attempted to dislodge the lance, for a potential weapon, but he gave up when he discovered that it was strongly wrought into the frame, as if it were another mast. He realized that the cost of the lance must be the breaking apart of the boat. A gray wooden raven was the figurehead, but it broke apart and fell into the water when he tried to examine it closely.

But the most disturbing feature, Perscors felt, was the gray sail. As the wind rose or fell slightly, it changed its shape radically, wrapping itself into cloudlike configurations that, even from as close as he was, could be read for their momentary resemblances: serpent, hog, horse, lion, and owl were among the outlines he could recognize.