Let me tell you what a noob I am. Are you ready? Here goes.
My big, ambitious megaproject for the fort-of-the-moment — Silvertouch — is an automatic wading-pond filler. And I'm struggling with it!
In my two entrance halls — the one to the outside world, and the one leading to the walled-off refuse pit/butchery/tannery — I've got little wading pits dug: ramp down, one tile of channel, ramp up. Fill it by bucket brigade to 2 or 3 and it washes my dwarves nicely whenever they enter or exit the fort. Handy.
But after I breached the cavern, I started to get plants growing in them, so I had to drain them. Then something else came up, I don't recall what exactly, and I drained them again. And filling them each time is a pain, and plus if I'm not exceedingly careful I get water between 2/7 and 3/7 and there's flow, and that probably isn't much but it can't be helping my FPS.
So I decided I wanted to create an automated filling rig. Dig a pipe from the brook, flood gate, more pipe, flood gate, then pond. If I did the math right, I could fill the tiles between the two gates with 7/7 water, close the outer gate, open the inner gate and drop exactly 2/2 on all the tiles in my pond. No evaporation, and also no flow.
How hard can it be!?
Well, it turns out it's quite hard, because I'm stupid. I can't seem to add up the number 2 a bunch of times and then divide by 7. So I place flood gates, try it, realize I got it wrong, move the gates, try it again … it's a mess. A sheer mess.