Chapeaugraphy, occasionally anglicised to chapography, is a novelty act and a busking trick in which a ring-shaped piece of felt is manipulated to look like various types of hats.
[1] The act originated in 1618 with Parisian street performer Tabarin, the most famous of the charlatans who combined a French version of commedia dell'arte with a quack medicine show.
He described his felt hat as "true raw material, indifferent to all forms".
[1] An 1899 magazine recounts "one or two smart English performers" of that time, including Alfred Leslie.
[2] Although rarely seen today, it was featured in an episode of Saturday Night Live in 1985, as performed by magician Harry Anderson.