Minimap magnifies a strip of ticks under the cursor.

Notes from the bench

• Each tick's height comes from a bell curve around the pointer, so neighbours rise together instead of one at a time.
• Spread matters more than lift. Too narrow and it looks like a single spike; too wide and the magnifier effect disappears.
• Fading the swell in and out on enter and leave stops the ticks snapping when the pointer crosses the edge.