I've just realised that I haven't written about my recent attempts at paper engineering so here goes.
This is an Archimedes Screw. Unlike "real" Archimedes Screws it won't lift water as it is made of card and acetate but it will lift salt. Very slowly and with a lot of salt not getting to the top but it will lift salt.
This Merry Go Round will indeed go around merrily. It is wind powered the wind being supplied by blowing hard on the vanes at the top.
But the tortoise. Ah the tortoise. When the handle is turned the tortoise types very slowly with one hand and scratches his head with the other. Reminds me of someone who lives in my house.