code: function(shapeFunc) {
      return function(node,x,y,size,color,context) {
        context.fillStyle = color;
        context.beginPath();
        shapeFunc(node,x,y,size,context);
        context.closePath();
        context.fill();
      };
    }
docs: For the standard closed shapes - the shape fill and border are drawn the
  same, with some minor differences for fill and border. To facilitate this we
  create the generic draw functions, that take a shape drawing func and
  return a shape-renderer/border-renderer
  ----------