This was a simple timer app I made specifically to go with a game that I received as a gift, "Boom Goes the Dynamite".
The rules state that if a timer card is played, you have ten seconds to make as many matches as possible. The rules also state that multiple timer cards may be played together and that wild cards may be played to add 5 seconds to the timer.
This all seemed like a lot to try and do at once, and having people count down is an unreliable/uneven method of timekeeping so I made this.
Working example can be found at http://dustinjray.github.io/dynamite