So, I've been staring at the NANOG70 tee shirt for
a bit now:
and I have to admit, I'm a bit stymied.
Usually, the tee-shirts are somewhat referential
to the location or to a particular event; but this
one is leaving me scratching my head.
Is it perhaps a shot of the network engineering
"Ooops (I broke the network again)" concert
tour?
Or is there some other cultural reference at
play that I'm not aware of?
Enquiring minds want to know!(tm). 
Matt
It could be this:
  https://en.wikipedia.org/wiki/Music_of_Washington_(state)#Grunge
Nirvana & Pearl Jam (amongst others) came out of Seattle, it seems. TIL!
It's a play on Pearl Jam's "Ten" album cover as best as I can tell.
-Jon
However, a Hyatt Regency hotel in Bellevue is about as far from grunge as
one can get. For those not familiar with Bellevue it is roughly similar to
Crystal City in Arlington, VA.
That's correct.
Andy
* David Barak [Mon 05 Jun 2017, 02:09 CEST]:
Ten (Pearl Jam album) - Wikipedia
Pearl Jam are from Seattle...
I only knew the CD version, which looks cropped from the LP edition: https://www.discogs.com/Pearl-Jam-Ten/release/376650#images/3899643
-- Niels.