Mug face puzzle. Mug face puzzle. find difference between the faces. A classic pub challenge, the Mug Puzzle Trick will certainly leave the audience puzzled. Eyes, ears, chin, front, nose, hair... Every part of the boy's face has to find its place on the board. A must for cognitive performance. A simple puzzle or a creative tool for exploring emotions and parts of the face. Bright, colorful printing on glossy stock is bonded with non-toxic, child-safe adhesive to solid wood blocks.