The famous Ebbinghaus illusion, named for its discoverer, the German psychologist Hermann Ebbinghaus (1850–1909). Despite appearances, the two orange circles are the same size. Have you ever looked at ...

Chimney sweeps repeatedly find nests and carcasses of birds and small mammals. Pigeons, blackbirds, and even squirrels often fall into chimneys. Most do not survive the fall. Jackdaws, however, even ...

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