Nim is played with what ever counters are available.
For our homework we are asked to play Tactix and try to discover a winning strategy, if one exists. T actrix is played by the following rules. The player taking the last pebble or stack of pebbles is the winner. If optimal strategies are used, the winner can be determined from any intermediate position by its associated Nim-Value. This is a great problem solving heuristic, called The Backwards-Forward Method.