Solving puzzles helps reinforce existing connections between our brain cells. Jigsaw puzzles are especially good for improving short-term memory. These two 1,000-piece dog puzzles by Eurographics are challenging but fun. The first is the The World of Dogs puzzle which measures 49 cm x 68 cm. The second puzzle is Dogs, Chiens, Hunde, Perros which measures 67 cm x 49 cm. Both were completed once and are in good condition.