[beagle3]

That’s interesting. I never “see” anything like that in my mind, but a few times in high school, I was explaining some geometric proof to a classmate; at the end, he noted that my verbal explanation and my finger pointing at the chart were compatible but out of sync with hand motion being about twice as fast, and then went to repeat both verbal and finger pointing, albeit at a slower rate, and they matched perfectly. This happened more than once though not many times, and I considered it weird but kind of forgot about it. This description makes me think I might have a mental canvas like this as well, except it might be a headless browser or something :)