I know people are going to want to make a lot of complicated mechanical devices, and I think we could use a few more tools to do so. I don't think any of these things were in the demonstration videos, but correct me if I'm wrong. The first thing I'd like to see is a gear-ratio block, ideally with an adjustable ratio. This way we can make things move faster than our turbines, with enough torque. Alternatively, you could use this to winch around things with enormous weight by hand, or otherwise without a huge turbine bank. I'd also like to use a block with a ratchet, for one-way motion. You'd also have to be able to release the pawl (a) by using the block. This way you could make a drawbridge that lifts slowly, and drops closed- or attach it to a counterweight and have the bridge slam up when you open the pawl. It would also be neat to have a mechanism to convert motion in either direction to one direction, for example if a wind turbine is subject to changing winds. The last thing, the one I'd really like to see, is a spiral torsion spring (or "clock spring") block. With use of a ratchet, you could wind one of these up as long as you want and unleash it when you need a lot of power. I don't need to convince you that your medieval doomsday weapon needs more power, do I? I think all of these things are pretty feasible, and useful. I don't know if any of them are redundant, or how they would play in to the sub-block system. So, how would you use these blocks? Can you think of any more mechanical components we need?