If you’ve been in and around downtown Oakland recently, you may have noticed the new mural going up on the exterior wall of The Greenlining Institute’s building. If you’ve stopped and taken a peek, you may have seen muralists at work on scaffolds and a swingstage, filling in details, painting portraits, and making the wall come to life.  Marina Perez-Wong and Elaine Chu, aka the Twin Walls Mural Company, have been putting in hours and hours of hard work in…