code: function validate(boxes, box) {
  	var a = box
  	for (var i = 0; i < boxes.length; i++) {
  		var b = boxes[i]
  		if (intersects(a, b)) {
  			return false
  		}
  	}
  	return true
  }
docs: determines if the region specified by `box` is clear of all other `boxes`