Here is another example that you block your opponent's punch with right arm, you then punch back with the same arm.
So now you've gone from simultaneous block and punch with two arms, to block then punch with one arm in two beats. Still not simultaneous attack and defense with a single arm in a single beat.
IMO, to use arm A to block and punch back with arm A is more risky then to use
- arm A to block, arm B to punch, or
- arm A to block, arm B to re-block, and punch with the arm A.
VT punching tactics are to use arm A to punch with automatic covering in one beat. Then follow with the same dual-function in arm B.
This is both faster and safer since you are punching with each beat while cutting off and controlling space to close recovery options for the opponent.
Requires squared facing.