Cut, slide, and unfold — every area formula is a scissors story, and every box tells two tales.
Pick a shape, size it with the sliders, and watch the scissors work: the gold dashed pieces show how every shape composes into (or cuts out of) a rectangle. The formula isn't a rule to memorize — it's what the scissors discovered.
Every factory order needs the right measurement. Commit first: does the job call for volume (filling the inside) or surface area (covering the outside)? Then the factory computes both and shows which one the job actually needed.
Three machines run the factory floor — each prints its cutting story, its packing count, or its coordinate walk.
Any triangle, parallelogram, or trapezoid — the machine retells its rectangle story with your numbers.
One box, two measurements: volume by cube-packing (½-unit cubes for fractional edges!) and surface area by unfolding the net.
Polygons built from vertex coordinates — side lengths come from the Submarine's distance rules.