Recover energy from gravity

[Gabriele]

Seems logic. But how you return to initial situation? you have to give the same energy you have gained... or not?  Perhaps if the black hose is weightless you can re-put inside the triangle gaining energy

[rc4]

Imagine the container like a disk (top view), triangle turn in the container. All black stems are fixed. The left position is like right position (return to initial position). Triangle is always inside water. Triangle pass through stems from right to left.

At final step, it's possible to move down grey rectangle because there is less up force, when all rectangle is there, move to the left and move up and repeat cycle.

[Gabriele]

Doesn't work.. Cause right covered surface is bigger than left...

[Gabriele]

in the case of a triangle and a rectangle too...

[Gabriele]

And the last shape too..