Draw a parcel, plot, or sensor layout, then transform it. The operations aren't canvas tricks — they're real Cl(2,0) geometric algebra: rotations are rotor sandwiches (R v R̃), reflections are vector sandwiches (n v n), and the area is computed from the wedge product, not a shoelace shortcut. The "Geometry underneath" panel shows the actual algebra each edit performs. Every operation is deterministic and reversible — undo restores the exact prior geometry.
Tap empty space to add a vertex. Drag a vertex to move it. Notice: rotating and reflecting never change the area readout — they're isometries, proven by the algebra, not enforced by hand.