Move the controls to inspect alignment. The rope and spring are drawn between explicit attachment points; mass labels and rulers are drawn in code. The artwork never decides the force, collision shape or spring constant.
The loading lift
Platform and parcel move together. The compact frame is an art preview; a full-height level needs correctly sized rails.
Crane crew
Rotation preserves beam anchors. Rope follows the endpoint. Counterweight mass and lever-arm length stay separate from appearance.
Bounce express
One fixed frame, one moving platen and one model-length spring. This control demonstrates the art, not a force calculation.