1. In a computational device providing a graphical modeling environment, a method for modeling a mechanical system having body elements movable in at least two dimensions, the method comprising: representing a first body element of mass of the mechanical system with a first block type in the graphical modeling environment, the first body element being capable of moving in at least two dimensions; representing a second body element of mass of the mechanical system with the first block type in the graphical modeling environment, the second body element being capable of moving in at least two dimensions; representing a third body element of mass of the mechanical system with the first block type in the graphical modeling environment, the third body element being capable of moving in at least two dimensions; representing, with a single constraint block of a second block type in the graphical modeling environment, one or more constraints having associated constraint equations between each of the first, second and third body elements relative to one another; and simulating behavior of the mechanical system, the simulating including solving the constraint equations of the one or more constraints represented by the single constraint block to simulate behavior of the mechanical system.