Now that it's too cold (for me!) to bike in Boston, I'm getting back into some crochet during my bus commute. Recently I've been working on making things that resemble proteinaceous capsids (not just viral, mind you, being a microcompartment fan myself).
Essentially these are constructed from many smaller crocheted geometric objects. To form the edges of each face, I switch (after a slip stitch) from crocheting in the back loops only to crocheting in the front loops only for one round - and then return to working in the back loops. This leaves a nice, hard edge.
More details and patterns to follow!