Rock: click corner by corner; click the first corner (or Enter) to close. Backspace removes the last corner, Esc cancels.

Pad: click on a flat (horizontal) rock top. Ships spawn on pads in order: pad 1 = player 1 …

Select: drag a corner, a pad, or a whole rock. Double-click an edge to add a corner. Delete removes the selected corner, pad or rock (corner only if the rock keeps 3).

Wheel zooms, right-drag or arrow keys pan, F fits. The faint circle at the cursor is a ship's size.

Publish adds the level to the online game (works from the home network for now; elsewhere use Download). It joins the N-key rotation; Publish & play switches everyone to it.