It's not easy. That is why it's 10 points!

OzOne wrote

On Mon, 26 Jul 2004 13:27:53 GMT, "Bart Senior"
scribbled thusly:

What does the following pattern represent?
[10 points]

1-2-2
2-2-3
2-2-5
3-3-6

I'll be the first to admit...I don't have any idea!

Oz1...of the 3 twins.