ad primitive graphics: As can be found in media folder, there are just two basic shapes provided to code, gray square and gray circle. I just love the ability of Gosu to set colour of image just there when that image is going to be drawn. When this feature is then paired with scaling...

Thanks! Yes, I was pondering how to show it but wind strength can actually change every update() which seemed a bit too busy to show. In the end I just tried to put more effects in but run out of time.

Good to hear you liked the physics part, honing it took quite some time. There is actually no collision detection, the model is based on https://demonstrations.wolfram.com/BlockOnAFrictionlessInclinedPlane/ which gave me the idea to let the barrel update its x-axis along the seasaw (and then get from that its coords via few triangles) instead of trying to directly calculate the effect of seasaw angle on its standard x, y coordinates.