This cornerless sanding block was designed for smoothing a shallow circular recess in a mold pattern. I have published it because A) I find its minimal, symmetrical, functional form pleasing aesthetically, and B) it achieves my longstanding desire to make a useful object out of the leftover bungs produced by the action of a hole saw. "Zen" derives from its minimal beauty and for its origins in nothingness.
The cornerless form is ideal for polishing surfaces. Because they are cheap, a whole brace of zen sanders could be easily manufactured in a range of grits and kept ready at hand. "Gray" wet-or-dry sandpaper was chosen over the "brown" varieties because it can be somewhat regenerated by washing and scrubbing with a soft brush, should it become clogged. To cut the pattern accurately, print out the image below, affix it to sandpaper with gluestick, and cut out both together using cheap scissors. Crimp the arms in two places with the lower bung in place, then remove it and make proper folds. 2" diameter bungs in 1/4" thick material are assumed.
Although manufacture of the sandpaper "starfish" is time-consuming and materials-inefficient, the methodical cutting and folding of the arms is conducive both of the solemnity and the attention to detail which are appropriate in the operation of sanding. Construction of the zen sander prepares the mind well for the task of sanding itself.