I've recently begun learning archery.
When you receive your first bow, one of the first things you need to do is set it up by adjusting the brace height, and add a nock point to your string. I'm not going to explain here how to do those things as I'm just a rank beginner. To accomplish those tasks yourself, you'll need a tool called a Bow Square, it lets you both measure the brace height and find the proper placement for your nock point.
These aren't expensive tools, you can find aluminum bow squares for as little as $15 online, but designing and cutting my own was a fun project, and was a good excuse to further acquaint myself with 10BitWorks' new 80Watt Rabbit Laser engraver.
I designed in Inkscape, exported to DXF and used LaserCut 5.2 to communicate the actual cuts to the machine.