Draining of Two Connected Tanks
When the filled tank on the right starts to drain, is there a time when the second tank (on the left) exceeds the level of the first? By varying the dimensions you can see that the second level will momentarily exceed the first for any setting.
This system is described as "A Neat Problem" and discussed by Prof. F. Wattenberg. He noted that it is equivalent to a simple network of two condensers and three resistors.