Drag a light's origin to move it. With Draw points on, clicking near an edge inserts a corner between those two nodes, clicking away from the shape extends it, dragging a corner moves it, alt-click a corner to remove it. Drag empty ground (or middle-drag, or scroll) to pan when zoomed in. The preview flickers exactly like the town's dark pass — same renderer, same math. The ground strip sits at the sprite's pivot so ground pools can be judged.