purpose of this elastic configuration

[coynold]

Hi docs,

I wore a "triangle" elastic configuration (elastic on each side around upper canine, lower canine, and lower first premolar) for about four months.

I am now wearing "upside down" triangles (elastic on each side around upper canine, upper first premolar, and lower first premolar).

I was just wondering what the purpose of these configurations? Is it to move teeth or line up the jaw? My ortho. never answered my question.