A classic toy, where each of the 25 blocks has four sides in solid colors (red, white, blue and yellow) and two sides are divided diagonally between red/white and yellow/blue, allowing millions of creative possibilities. Introduced in the 1920's and often used by psychologists to test critical thinking skills, this toy will improve a child's visual/spatial reasoning while providing hours of fun. Winner of the 2003 Creative Child Magazine Seal of Excellence. Includes a sturdy wood tray and pattern sheet. The blocks are 30mm cubed and painted with non-toxic colors. Made in China. For ages 3+.