Another type of simple machine, besides the lever, is the pulley. Pulleys can be fixed or movable, and they can be used singly or combined with other pulleys to make pulley systems. Take a look at this clip to learn a little bit more about pulleys, and be introduced to the idea of mechanical advantage. And here’s Tim and Moby’s explanation of the same concepts. If you want to go further, try reading this.
And finally, once you have understood pulley systems and mechanical advantage properly, you can demonstrate your understanding by designing a pulley system to lift an elephant off the ground into a truck of height 1m. I can’t wait to see what you come up with!