New painting

I've always wanted a painting or a poster or a print of the complete alphabet, but I've never been happy with what's out there. And with my side project, twenty-six in fifty-two, I've been thinking of letters constantly! When I walked into Curry's art supply store a few weeks ago, I was inspired by this 3' x 3' wooden panel canvas — it reminded me a scenic theatre flat.
So I started drafting out how I wanted this piece to look:
I knew that I wanted to incorporate alphabet, squares, and the inherent mechanics oh the letters (similar to Durer Caps). I also wanted to create a system-based geometric sans serif, inspired by a couple of my favourites: LTC 20th Century and Toronto Subway. But above all, I wanted it to be simple and neutral — something I could look at every day.
Here's the graphite drawing on wood (click to enlarge):
Here's with a ghost-like white wash inside the enclosed characters:
Some outlined squares added:

And, the final result:
Originally, I thought I would be more liberal with revealing and redrawing the mechanical lines and shapes, but I opted for this less-cluttered format. I'm going to let it live on the wall for a while and see if it needs more.

(Special thanks to everyone who offered advice and feedback along the way!)