Rod: press-drag from any glowing rim dot to another — no menu needed (or use the Rod button). Wheel: drag the Wheel button onto the board (or tap the tool, then tap empty space). Belt: pick the tool, then tap two wheels (crossed = reversed spin). The motor spins on Run. Rods only rock; belts rotate. Over-strained rods snap. While paused, tap a rod/belt to delete it, or long-press a wheel to remove it.