I thought I would have a go at recreating the classic "picket fence" in Algodoo. I couldn't use a light-gate so I used a light gate and a heavy fence. I wasn't easy, the spring is heavily damped, the gate has zero restitution as does the little orange block and the fence. The fence is kept vertical by two hidden rectangles and g is about 2 ms^-2. The graph shows the force on the gate from which you can extract the times to give a nice parabola when plotted against distance.