Since the design is modular, you can obtain mechanical advantage at different rates by using any number of rollers and blocks.

In order to gain this mechanical advantage, I designed this block and tackle system with fusion360. I used 8 reels and 10 blocks in the design. I printed these designs with a 3d printer. The reels were printed with a 90% infill rate and the blocks with a 50% infill rate. It looks pretty solid, but for high strength, I recommend printing with high filling ratios (90%-100%).

I used M8 half thread bolts to attach the blocks together. The lengths of the half thread bolts are M8x50, M8x70, M8x90 and M8x110 mm. Meanwhile, the thread length of the M8 half thread bolt is 22 mm. At the same time, the rollers roll over these half-tooth bolts.

First I tested the efficiency of these 3d printing pulleys with a mini dc motor. Then I removed a few items. I reached the triple tackle result of the most efficient system. (In other words, the pulley system providing a mechanical advantage at the ratio of 6:1) In fact, it is thought that the highest result will be obtained in the quadruple tackle (8:1) system. But frictions hinder the mechanical advantage we need to gain. Therefore, in the Quadruple tackle system, the motor did not lift any more force.

(I made 2 different eye designs, you can print whatever you want.)