Colorful illustrations and photos accompany step-by-step directions in two spiral-bound entries in the Paper Magic series. Paper Tricks by Alan Folder, illus. by Maureen Galvani, shows aspiring ...

Just as our visual system strains to see the vase and the two faces at once, we struggle to conceive of a motion that has a dual motivation: to put and to fetch. A paper by Van de Cruys, Wagemans and ...