The Mad Chair: When prisoners began to tap on pipes and whisper to each other through vents in desperate need of human contact, the consequences were severe.
One method of (torture) punishment was the "mad chair", in which inmates were strapped so tightly that their circulation was cut off, left to sit for days without food. In the best cases, limbs had to be amputated. In the worst, prisoners were driven to insanity. @easternstate