A Real Data Structure Tree

Description

The image shows a leafy tree or shrub hanging downward from the underside of a stone or concrete arch, with its root area apparently fixed above and its foliage suspended below. There is no overlaid text in the image; the sibling post caption says, "Finally, after years of search, I found a real tree." The joke is a literalized computer-science tree: unlike botanical trees, data-structure trees are usually drawn with the root at the top and leaves below, exactly like this upside-down plant.