Piet Mondrian was an early 20th-century abstract ... But, in “Blooming Apple Tree” (1912), all the lines are the same thickness. The scaling is gone, and with it, the tree.

Even abstract paintings such as Piet Mondrian's 1912 cubist Gray Tree, which doesn’t visually show treelike colours, can be identified as trees if a realistic value for α is used, researchers say.