Double pulley- OpenScad

On board of ships we often use pulleys, usually single one, to heave up a load. Sometimes we need to transport a load horizontally. In this case double pulley comes handy. What about making one for both horizontal and vertical transport?

Here is my idea.
Plastic plate (depends of thickness) could be used for lightweight loads or as pattern to make steel one. With steel plates it should work with loads up to 100kgs (no guarantee- not tested) what is enough for hand work.