re #3, i believe ive read of a small engine (very small) that works on the principle of warming gas expanding and cooler gas contracting. If memory serves its used in clocks and things. you personally dont have to add a single bit of energy, but the changes in room temperature from day to night is enough to wind its spring. If i remember correctly (its been decades) someone suggested having something simular to build a huge facility to get the difference in the air and water to drive electric generators. Obviously nothing ever happen with it. Likely someone with a little bit of understanding of physics and engineering came along and found the problems with it in short order. This is likely to be as close to perpetual motion as well ever see.

the more man learns, the more he realises, he really does not know anything.