The mechanism of flea jump is based on the principles of elasticity that converts the stored mechanical energy into kinetic energy through the expansion and contraction paradigm. The Expansion and Contraction Paradigm (Bigger & Smaller or Stretching & Shrinking) is directly related to such principles. Based on the principles of expansion and contraction man has invented number of interesting design concepts and developed products. Its basic principle is stretching and shrinking, like rubber band. The operation of catapult (plate 27A &B) is basically based on the jumping technique of flea.

Plate 27A Roman Catapult	27B Operation of Catapult	27C Flea Jumping

Plate 28A Position-1	28B Position-2	28C Position-3	28D Slingshot