A few weeks ago, I saw a Twitter post by Team Reptile (The creators of Bomb Rush Cyberfunk, Leathal League and Hyperfunk) announcing that they are looking for a 3D environment artist. The Job application required for an artist to pass a test - This was my submission. The applicant was to create a building and make sure it was under 1000 Triangles (the whole scene, excluding the placeholder character, was 800+ Tris)
Opting for a stylized gas station, I created a very rough mockup with a few loose guidelines and freehanded it from there.
The basic shapes, outlines, etc were created in Adobe illustrator, then finalized in Photoshop. The whole task was a one big learning experience that I was glad I had to go through.