# For the center point CCCC, the image C′C’C′C, prime is at the same point as CCCC.

Jack tried to define a rotation.

For the center point CCCC, the image C′C’C′C, prime is at the same point as CCCC.
For a point PPPP that is not at CCCC, a rotation of θ\thetaθtheta about point CCCC creates point P′P’P′P, prime, such that CP=CP′CP=CP’CP=CP′C, P, equals, C, P, prime and m∠PCP′=θm\angle PCP’=\thetam∠PCP′=θm, angle, P, C, P, prime, equals, theta.

What mistake did Jack make in his definition of a rotation?