The changes on the image cards are based on value and hue. Ask children which image is more attractive, has clearer details or stands out more to them. Children arrange matching cards from darkest to lightest. This game encourages children to understand gradations of hue and the impact it has on images. Contents: beech wood frame holds ( 400 x 400 mm ) 36 plastic image cards (2.5 mm) Puzzle Size: 400 x 400 mm