And here’s the fourth Zone Mortalis tile:
Having remembered that sponges exist, I tried using them for the highlights on the concrete. It was so much easier to get a consistent result than mucking around with the dodgy old brush.
I also decided to try out yellow tiles. Yup, that’s yellow. I’m not going to bother with hazard stripes on this one, but I might do on another one.
@Nicodemus if you want this yellow, it’s Steel Legion Drab → Averland Sunset → Flash Gitz Yellow 
One off the pile.
BATG Score: +53
