What’s the back story to this BART station graffiti wall?

How many San Francisco graffiti artists can you spot in this photo. Reader and keen urban observer Cole Brennan (Belle_Cunningham on Instagram) spotted this wall of graffiti signatures, on which the cleaning crew and artists seemed to have reached an accord:

Most graffiti gets cleaned off of the Muni system pretty regularly. Not so with the back of this map, which puts a neatly partitioned blank wall on the landing of the long stairs up from Bart. The graffiti artists and the cleaning crew seem to have some sort of detente worked out for this wall. I spend way too long trying to read it all, searching for new tags and regulars. That Rveng is classic, and you can’t throw a rock in this town without hitting something Zamar has tagged, but this is the first I’ve seen of Croak. Visiting artist? New tagger? Oldtimer just switching it up?

I’m no graffiti artist, and I won’t pretend to love all of it. Certainly, some tags demonstrate nothing but dull, amateur hubris. The good tags have a confidence that I admire, though.

Here’s an interview with Zamar, who created the mischievous squid seen all around town.