Hum... The hydraulic analogy is for school kids to learn what electricity is. If you are creating circuits to hook into an arduino, you should have moved from it already.

It is a flawed analogy but it behaves like a fluid more than most realize:

https://youtu.be/2AXv49dDQJw?feature=shared&t=1248

Electricity behaves a lot like a fluid. But not much like water or air, so there's little point in using it as an intuitive analogy.

I believe school kids should be already creating circuits and hooking them up to arduinos.

I feel insulted.

Instead, if you still use it, just drop it because it's probably holding you back.

And if you managed to move ahead in hard mode, you shouldn't feel insulted.