Froebel’s Kindergarten curriculum is considered the first to include the systematic use of blocks to help children learn through play. Gift No. 6 was a 3-inch cube divided into 18 rectangular blocks, 12 flat square blocks, and six narrow columns. Children could use these new sizes and shapes for different building forms; learn about area, volume, scale, and modularity; and form symmetrical designs using balance, simplicity, and strength of center.