What is "squirrel cage"

alt. 1 A circular cage for a squirrel or other small animal, which rotates vertically as the animal runs at the bottom. 2 (context figuratively by extension English) A tedious, repetitive, unfulfilling activity or situation, especially one in which no progress is achieved. 3 (context engineering English) Any other device, such as a fan or rotor, that resembles a squirrel cage in form. n. 1 A circular cage for a squirrel or other small animal, which rotates vertically as the animal runs at the bottom. 2 (context figuratively by extension English) A tedious, repetitive, unfulfilling activity or situation, especially one in which no progress is achieved. 3 (context engineering English) Any other device, such as a fan or rotor, that resembles a squirrel cage in form.

n. cage with a cylindrical framework that rotates as a small animal runs inside it