River North [Bas Relief on Tree Studios, Annexes and Courtyard..]

I am very curious..
What's the story behind this?
It's part of the bas relief on Ontario Street Annex of the Tree Studios, Annexes, and Courtyard, click here..

Who are these people?

One of the most annoying pay-for-parking sign, just in front of this beautiful relief work..

Tree Studio, Ontario Street Annex

RELATED LINKS..
# River North: Tree Studios, Annexes, and Courtyard..
# River North: Medinah Temple...
# River North..