16 +/- Counters

After realizing that the [64 +1/-1 counters](http://www.thingiverse.com/thing:1970114) where to small, I headed out on an epic quest to make a more usable counter!

After a few mistakes, I finally came up with a nice design :)
These are the ones that I now use in every game for myself.

A counter can be either + or - so while it's not as easy to use as the [+1/-1 counters](http://www.thingiverse.com/thing:1970114), It should be usable, especially considering that most players use glass pebb