Back to playing with the idea of a cleaner - it just occured that many brag about how tight an intersection they can manage, but I haven't see one which claims to do a 90 x 90 corner - of which I have 2 - both are on a wall hugging the fence line, if that explains the complete lack of radius on the intersection of both south wall to east and west walls.
There is a tiny radius between the floor and the south wall, but not much.
Should I count on going out every 30 minutes and freeing the cleaner from the corners?
The 3 steps are also square blocks, but are easily reached.
As always, thanks for any info!