We finally settled on a greys, blues and greens, and I just assigned them to random aliens. But that big spaceship one that's worth a massive 1,500 points, I made it tangerine. Because it's awesome. And also, I love tangerine. I used a sketch for the background because I thought a solid black might be too flat, especially since I was using all solids for the aliens.
And I'm toying with the idea of writing this up as a pattern... Sort of have to figure out what to call it if I do! The hubs was like "Uhh yeaaaaah you can't call it Space Invaders"... Yeah, no shit, Sherlock.
I've since added two more alien blocks and will make doubles of all the greens, blues and medium grey ones. Can't wait to see how this one looks all finished!! :)