Imagine a cylinder 1/8 inch long (3.175 mm) and 1/16 inch (15.75 mm) in diameter. The place I work makes parts for other companies. Yesterday we made these tiny little pins. But when inspecting them to make sure they were the correct size some were found that were not. The length can be off by 1/1000 of an inch (.0254 mm) and it is acceptable, but some of them were off by 12/10,000 of an inch so hundreds of them had to be measured one by one to cull out the short ones. That, among other things, is what I did at work today.
Now I'm home. Time to check out my new Professor Pyraminx.