Stopping back at this thread a moment because I need to tell you my most common thoughts in a moving vehicle are to do with estimating speeds and distances multiple ways and seeing how close I can get while still approximating things like "car length = 2m" or "building height = 2 storeys = 2 x (2.5m + 1m) appearing half the height of that hill over yonder which is approximately three times as far away". I'll do this in different ways and see if they all agree. I'll often get stuck in rabbit holes of things like working out the speed of light in terms of pedestrians or angle of sunlight based on which way the train was going before it annoyingly went round a bend to throw me off.