Cutting through an onion is always intriguing! I like to observe the layers and in particular the middle bit, where it might be more green than the rest of the onion. All onions have the concentric rings but the variation is interesting.
Ditto with celery. Only this time I had the presence of mind to photograph the cross-section now, and not put it on my photographic do-to-list at some indeterminate time in the future.