One of the first items introduced in the Sensorial Area are the four cylinder blocks, each containing ten knobbed cylinders of various dimensions. The purpose of the cylinder blocks is to develop visual discrimination of height and diameter. The students are first introduced to cylinder block 1, which decreases in both height and diameter. After the student has used each of the four blocks individually, they move on to using two, then three, then four together. They may match them by distance by placing the cylinders in another area of the classroom, then bringing back a cylinder to correspond with a specific hole. Eventually students may enjoy doing this activity blindfolded. This material helps develop concentration and focus, independence, fine motor control and coordination, refinement of voluntary movement, and is a preparation for later mathematics. This link gives information about the introduction of the cylinder blocks.