jdege

The other grooves are for the clips that hold the top and the shelf in place.

It's not possible to clean a floor using only a string mop.They're intended to get water off the floor, not to scrub away dirt.

My workbench has benchdog holes, so I can drop in a benchdog anytime I need a planing stop. If your bench doesn't have benchdog holes, but does have a vice, this would make a very clever solution.https://www.instructables.com/id/Building-a-real-w...

I'd worry about the wall shifting, over time.It's usual to place deadman anchors or tiebacks to support a retaining wall.https://www.bobvila.com/articles/retaining-wall-repair/#.WicVIEqnGw4

I tried using a box fan, it leaked too much air through the corners to be effective. There are fans that have round housings, one of them might work best. But I didn't have one. If I were making something intended to last, I'd probably find one. But for a duct tape and cardboard solution, I use what I have lying around.