There's another visual/mental exercise I discovered on my own as a kid.
For some reason starting with a blank slate, in my mind I cannot draw a spiral from the outside all the way to the center. I can cognate what will happen, but I can't watch it proceed. It never gets there. As it runs out of room there is an apparatus in my brain performing a "zooming in" of some kind (to look at it closer perhaps?) This widens the space left to spiral into and I cannot ever smack into the middle.
WARNING: You have now entered a no @#$%tard zone. Please gather your anti-vaccine propaganda nonsense and slowly back out the way you came in.