         # Update the element's state.
         @setPosition(position)
         @setVelocity(velocity)
+        return this
 
     # Apply the given forces to the element on the next step of the simulation.
     addForces : (forces...) ->

        resultant = @forces.reduce (t, s) -> t.add(s)
        @applyForce(resultant, milliseconds)
        @forces = []

    # Return true if this element intersects with the other
    # element, false otherwise.

        return this if @isStatic()
        velocity = @getVelocity().add(impulse)
        @setVelocity(velocity)
        return this

    # Apply the given force to the element for the given number of
    # milliseconds.
