the Internet Backbone

Perhaps you can tell me where PSI connects, good sir...
By my count it's MAE-East and CIX and nowhere else.
There are a few major backbones not at the Chicago NAP.
And none of the majors are at MAE-Chicago or any of the MAEs other
than East and West.

PSINet connects to MAE-west, MAE-East, MAE-East+, CIX, and the
SWAB (little known SMDS Washington (DC) Area Bypass).