public override Shape clone()
{
var clone = new ChainShape();
clone.shapeType = shapeType;
clone._density = _density;
clone._radius = _radius;
clone.prevVertex = _prevVertex;
clone.nextVertex = _nextVertex;
clone._hasNextVertex = _hasNextVertex;
clone._hasPrevVertex = _hasPrevVertex;
clone.vertices = new Vertices( vertices );
clone.massData = massData;
return clone;
}