Disclosed is a system and method for generating a universally usable, completely automated public turing test to tell a computer and a human apart. A controllable buffer is inserted in a specific level of a clock tree, and a controller is provided for adjusting two clocks with different skew by controlling the PMOSNMOS arrangements in the controllable buffer so as to generate more current for compensating the time delay of slow clock to a sink. The tensile portion includes flexure slots extending from its sides beyond a longitudinal central axis to a terminal bottom. Once the squirrel cage is created by the stator field and a current induced, the motor operates as a conventional squirrel cage induction motor.