\begin{definition}[Definition:Matching Pennies]
'''Matching pennies''' is a two-person game whose mechanics are as follows.
There are two players: $A$ and $B$.
Each player puts down a coin, traditionally a [https://en.wikipedia.org/wiki/Penny penny], either head or tail up, without showing it to the other player.
The coins are then uncovered.
If they both show the same side, $A$ is deemed to have won, and he takes both coins.
If they show different sides, $B$ is deemed to have won, and he takes both coins.
\end{definition}