After printing IronAwe's great circle-square i found it hard for my buffalo fat fingers to hold the square, wood dowel and my pencil all at same time. Thought if it had a thumb grip on it, i could push it against the wood while pushing it up to the square. This is the out-come of my thoughts and seems to work well for me on those real small dowels i use. Make sure you have "Cool" turned on in Skeinforge and not to scale it down too small. Also, if your printer prints tall items with a bit of slope, right after printing while it's still hot and on the build plate, grab a small wood dowel and hold it square against the square edges and hold/push the thumb support square while it hardens. Just a thought. Mine printed well, hope you enjoy, Rick.