how to determine whether a given stepper motor is unipolar or bipolarr

Stepper motor consist of a permanamt magnet rotating shat, called the rotor, and the electro magnets on the stationary portion that surrounds the motor, called the stator. One complete rotaion of a stepper motr. We can see that the motor is beginning at the upper electromagnet, which is currently active ( has voltage applied to it). To move the rotor clockwise(CW), the upper electro magnet is deactivated an the right electro magnet is activated, causing the rotor to move 90 degrees CW, aligning itself with the magnet. This process is repeated in the same manner at the south and west electro magnets until we once again reach the starting position.