A flattened cross-section of a worker bee's gut, driven by the same flow model as the 3D lab: nectar cycles inside the honey crop, the proventriculus filters pollen from nectar, and particles shrink and fade as nutrients are absorbed through the midgut.
The tube's local radius and colour follow position t along the gut exactly like the 3D revolved mesh, just drawn flat — nectar particles largely recirculate in the honey crop while pollen grains pass the valve and shrink as they're digested in the midgut.
Raise nectar concentration to swell the honey crop, raise pollen protein load to speed absorption in the midgut, and toggle the proventriculus filter off to watch nectar and pollen flood through unfiltered instead of nectar being retained for storage.
The honey crop is nicknamed the "honey stomach" even though no digestion happens there — it's a dedicated tank so foragers can carry nectar home and regurgitate it to nestmates or have it ripened into honey.