So I know it's possible to rotate blocks in 90 degree increments with R, and you can change the spin or direction of moving parts with F,
but we need one more function... and I can really only think of one use for it at the moment (but I'm sure there will be other reasons
for it in the future)

We need to be able to flip or mirror propeller blades. If you're making a flying machine with clusters of propeller blades to the left
and right, like this i.imgur.com/uNV6bva.jpg

you currently have 2 options:

A) Make both sets spin the same direction, which provides either lift or downward thrust depending on the direction of the spin, but
does not allow the propellers to counter-rotate each other.. so your vehicle will always corkscrew to the left.

B) Make them spin opposite directions, which looks better, and allows them to counter-rotate each other for balance (preventing the
corkscrewing)... except it causes one to push up, an the other to push down, because of the angle the blades are carved into.

When attempting to rotate the blades themselves, you can orient them upward or forward... hitting R twice to rotate them a full 180
gives the same result as not rotating them at all, since the top of the blade and the bottom of the blade look exactly the same (as
they need to, for the propeller to work properly).

But if we could FLIP or MIRROR rather than rotate, we would be able to actually create a blade that is the opposite shape.. so even
though the propellers are spinning opposite directions, they will still generate lift, while also giving counter-rotation to each other to
prevent the vehicle from spinning wildly out of control.

This would allow us to make stuff like the medieval equivalent of one of these m8.i.pbase.com/g6/71/720771/2/69203878.7OhkVFa9.jpg