Selected Control Point
Click a point on the mesh.
Matrix Scaling
Corners are curve start/end points. Points between corners are Bezier controls.
Drag points to edit them. Shift-click points to select multiple, then drag one selected point to move the group.
Drag empty canvas to move around. Shift-drag empty canvas to move the whole shape.
The matrix format is rows separated by underscores, points separated by pipes.