Whenever a creature you control with power 2 or less enters, you get an experience counter.
At the beginning of combat on your turn, put X +1/+1 counters on another target creature you control, where X is the number of experience counters you have.
All experience counters are identical, no matter how you got them. For example, the last ability will count experience counters that you got from the first ability, from another ability, from proliferating, and so on.
04-11-2015
wotc
Each game pack includes a card labeled "Experience" with the suggestion "Place your experience counters here." This card isn't required for play. It's simply a convenient spot to put your experience counters, which can be represented with dice, glass beads, or other small items.
04-11-2015
wotc
Experience counters are the second kind of counters a player can have, joining poison.
Random a card of Magic: The Gathering (MTG), but you can also roll the D20 dice, random a Planeswalker, have fun with the random rules and more.