Jointer-free way to square edges is on the level

Because my wife and I spend each winter away from our home and shop, I often have to woodwork using a minimal set of tools. When I needed to square up the edges of a few pieces for a panel glue-up without access to a jointer, I came up with this simple trick.
I adhered a strip of 120-grit sandpaper to the edge of a 4' carpenter's level, clamped down the workpiece, and sanded until the workpiece had a flat and square edge.
—Charles Hughes, Westfield, Iowa