Yes! I'm still going through this series of tutorials! It's hard to find time between my day job, settling personal issues (I'm moving back to Singapore in April) and Hearthstone fanart but I managed to squeeze out some free time to complete the assignments for the 3rd and 4th week.
The week 3 assignment was material studies. Instead of doing material spheres (which seems to be the norm nowadays), we were instructed to do more traditional still-life studies. Although one of the requirement was painting from life, I had difficulty amassing interesting objects within my apartment to paint. So for this exercise, I used photographs taken by other photographers. Here are their 500px pages if you're interested in doing some studies yourself:
The week 4 assignment required us to produce paintings of the same objects under diffused and direct lighting. I couldn't find any stock imagery on the web that satisfied this condition, so I had to make do with what I had at home. The only direct light source I could simulate was with a torch light and the final results were not very different from diffused lighting.