Hello guys, you have an interesting thread going but I am afraid this is not going to work. Let me explain why I think so. In your second frame Naboo you show all tanks being equally filled. I am thinking this is where everything will stop. If I understand you correctly you are thinking the water in the top left tank will flow into the bottom left tank causing the air pressure to rise in both tanks. This in turn will push the water out of the lower right tank into the upper right tank. I think you have missed the fact that when the air pressure rises in both lower tanks then it will be pushing back up on the water trying to come down from the left upper tank also. I think you can build a cheap model to check this out using some 2 liter soda bottles and some rubber tubing. You could hot glue the tubing to the bottles and use clothes pins or small clamps to pinch the hose together instead of buying valves. If I have misunderstood please accept my apologies. Just trying to save you some trouble and expense.

Best wishes, citfta