Martin Gardner reported a case of No. 3 on people becoming mad after mistreating their minds with "Hinton Cubes".

Indeed, Gardner prints such a letter in the midst of introducing those very cubes to a larger audience. I presume that the letter is the work of a joker or crank, as it appears to be.

The unlucky practitioneers of a cult Hinton made out of that got mad because the trained ways of modified perception started working automatically, they could not stop that any more.

Citation needed.