RectNode constructor.
Width.
Height.
Optional
x: numberInitial position-x.
Optional
y: numberInitial position-y.
Protected
_SVG <rect/> element.
node force-x
node force-y
Rect height.
SVG node ID
node mass
node momentum decay factor
node momentum-x
node momentum-y
node electric charge
Rect width.
node position-x
node position-y
SVG <rect/> class. Behaves like a particle with an electric charge.