The concept is similar to the three man mechanic. The T never crosses the court during live ball action. The L may opt to rotate over to the strong side to get a better angle for post play and entry plays coming into their primary.
In this manner, you are able to help with off ball picks, swim moves and cutters in the paint. It's more difficult to see these plays if you are looking through the players with the defense generally in front of you.
Warning: If you do this remember three things.
1. Make sure you pre-game this and your partner is
experienced enough to "handle" the rotation. Other-
wise, you may find him "rotating" with you to main-
tain the box.
2. When you rotate, remember that the opposite side-
line is still yours, and that you have to rotate
back over in transition.
3. Don't bother rotating if all you're going to do is go
get a better look at the ball handler in T's primary.
)