The Memory (aka Concentration) Game - The Essential Guide to HTML5 - page 143

When two cards match, the application removes them and notes the match in the form (Figure 5-3).
Figure 5-3. The application has removed the two cards that matched.
As illustrated in Figure 5-4, the game displays the result—in this case, 6 matches in 36 seconds—when
the player finishes.
Figure 5-4. Version one of the game after the player has completed it.