I was putting up some wall decorations earlier today and was painstakingly realigning everything until it looked level to my eyes. It might be just a hair off, but if I don’t correct it, I’ll see the misalignment almost instantly and get bothered for the rest of time until I fix it. Has anyone investigated, or is there literature on the minimum perceptible angle from level to the naked eye?
I recall a carnival-type installation, were a whole house was built at an angle, and at the end of it they had a water spigot they turned on, and the water flowed “uphill” (to the human eye).
I’ve been to one of these! There was a hill within the house that is way steeper than it looks and it was super freaky and disorienting. Just being in that place gave me motion sickness