Hello, I recently got a book called Figure Drawing For Concept Artists by Kan Muftic and there’s a bit about Reilly rhythms in there. It’s not very in-depth or but thought I’d point it out. It’s a beautiful book. As others have mentioned, Watts Atelier is probably the best place to learn about Reilly rhythms.
I agree with Kristian that some of the shadow/anatomy shapes could be clearer. That would make the light source read more immediately to the viewer, and would help the portrait sit in space more solidly. However, this has a lot of energy in it and is really playful, and I appreciate that a lot. Well done overall.
Hey Eric! This is an awesome drawing! You're definitely getting a hang of the concepts. What I would say is everything is in the correct spot, but it looks like there are a bunch of arbitrary shapes. The neck for example doesn't feel like it has any primary forms. And the anatomy doesn't feel correct. So as a result when you cover the head and look at the neck, you can't really tell what you're looking at. @Stan Prokopenko has an awesome diagram where he shows how using a very strong primary cylinder can be used as the scaffolding for an arm. If you were to use the same concept for the neck of this drawing, I think it'd make it more dynamic.
I started the Proko portrait course approximately 2 years ago. I feel I’ve made great progress since then and am still working on it. Here’s my latest. I initially found that drawing heads was very difficult, and the course was helpful in breaking things down in a way I could understand.