These are really good, @Regina F! All the various angles clearly convey the forms of the head. I can se you're "thinking in 3D" when I notice you're drawing cross-contours through the forms and showing even the "hidden" parts. I understand how it must have been a helpful attitude to practice just the cranium / sphere first, so great job taking that step. Also, it's good to know that the 3D model helped - if you drew all these heads using the 3D model as reference, maybe now you could try practicing a few from memory or from imagination? One nitpicky suggestion I'd have would be to remember to always keep an eye out for proportions. When I look at the Loomis heads page, I see some drawings with pretty consistent proportions (for example, the two ones on the uppermost right and the other two on the lowermost left, and even the foreshortened ones in the middle), but I also see a few where the proportions got slightly skewed (for example, the second one from left to right on the upper line and the one on the bottom right corner seem a bit too squished / narrow). Nothing that a few quick adjustments wouldn't help - as I mentioned, this is a nitpicky observation. Just something to be noted. Overall, of course, you don't have to worry about getting proportions right all the time in the first try - as long as you're aware to make proportion-checking a habit within your drawing process over the long run, you're good to keep going. Hope this helps! Please let me know in case you need any extra help.