Another core idea is that one uses:

Circles to Deflect, Squares to Attack

This means that moves that are considered offensive will follow straight lines. Moves that are defensive will be circular.

Defensive Moves are Ward Off and Roll Back. These two moves are actually mirror images of each other. They both draw a line around the body as the arm sweeps through space, with the hips the center point. It’s as if one is wearing a barrel which spins around, deflecting attacks.

Ward Off is considered Yang, powerful, and is used to push an attack away.

Roll Back is considered Yin, soft, and is used to deflect and redirect an attack.

Offensive Moves are Push and Press. The other Moves are also offensive, but are considered secondary. They will be covered later.

Push covers all and any projection of energy in a straight line away from the body. A punch is a Push. A two-handed shove is a Push. A Push is like shooting an arrow.

Press is a compression strike, sending a short shockwave through an opponent. The energy is not sent through the opponent, but into his or her center. A Press is like slamming a hammer down.

Pluck, Twist the Joint, Elbow Strike and Shoulder Strike are offensive moves which are less general than Push or Press. They have their own bio-mechanics and can only be used in specific ways. Push and Press, on the other hand, describe types of energy.

http://www.youtube.com/watch?v=gzDW_cgQYhc&feature=plcp