Type the the letter before it falls down. If you type it when the top of the letter is in the green zone, you will be rewarded three points. If the top of the letter is in the yellow, you will receive only one point. If the top of the letter is in the red, you will loose one point.
I made it all. I made it because I was bored. DISCLAIMER: THE LETTERS AND THEIR POSITIONS ARE RANDOMIZED, ANY WORDS CREATED ARE PURELY COINCIDENTAL.