This example is similar to the other area detection example - however it's more refined, uses 'slightly' more sophisticated code to detect the certain areas, AND is more fun to play with.
When you start the example, you will see three blinking dots towards the bottom of your picture. These are the hitpoints where the motion is sensed.
Area Detection example 2
I've found that raising your hand up relatively quick up into the picture works quite well! It's way more useable than the first example - in my little honest opinion