Add as many counters as you need to the screen and position them to your liking.
Tap the small minus circle to reduce the counter by one, and the big circle to increase it by one.
Use the pencil button to scribble notes or labels onto the screen.
Multi-Touch support so you can increase multiple counters by tapping different fingers, or work with another person with your own counters on the same screen.
Too many counters on the screen? Just drag one to the trash button and its gone for good.
Practically no limits! The counters can go very, very far into both positive and negative numbers.