How does it do this?!?!

Heheh - I've seen these before. They're very cool, but you want to know how it does it?

Six different colors, five numbers in each color. 30 numbers total. When you choose your number, you tell the program which color it is, thus narrowing it down to five. The next (color) step is irrelevant. Then the houses. Five houses, six numbers in every house. If you went back to the original page (which you can't without reloading the whole thing) you'll see that there is one number of each "color" (again, from the first page) in every house. So if your first number was green, they separate all the green numbers so that there is only one green number in each house. Once you pick your house, the program knows exactly which number you chose. Then it has your number show up behind the first door you click on. Yay, I figured it out!