Not being much of a gearhead, I was a little apprehensive of tackling Gears designed by Hirokazu Iwasawa (Iwahiro). It is a 2D restricted-opening packing puzzle made by Constantin Puzzles that Iwahiro used as his exchange puzzle at the 41st International Puzzle Part (IPP). It consists of a frame with a hinged door on the side that can be opened to allow gears to pass through. There are 9 gears in all. 2 of them are fixed in the center of opposite sides of the frame and can rotate freely. The remaining 7 loose gears are the same size and have the same number of teeth as the fixed gears except for 1 that lacks teeth. The frame also has a large opening in the clear acrylic top in the shape of an I to provide a means of manipulating the pieces when they are inside. Lastly, there are a couple of pointy bits in the frame to throw a wrench in the gears.
The objective is to add all the gears to the frame and close the door. I started to putter around with adding gears but it took a while to get the gears turning, in my brain that is. It all starts out easy enough, but as more gears are added, they need to rotate as they pass through confined spaces eventually leading to gears disagreeing on which direction they should be rotating.
Shifting my brain into high gear, I finally settled on where the toothless wonder needed to be. Of course I tried all the other places to rule them out for certain. Even then it was not obvious to me how to proceed. Eventually, I shifted gears and tried something a bit more complex that set the machine in motion and allowed the lid to close with all the gears inside. A very nice AHA moment.