This engine was developed to show one of the uses of Reuleaux Tringle. This triangle is a geometric form of a equlateral triangle witch is constructed by drawing arcs from each polygon vertex of an equilateral triangle between the other two vertices. Because of this, it can be rotated inside a square. They are named after Franz Reuleaux, a 19th-century German engineer who pioneered the study of machines for translating one type of motion into another