Draw the putterhead straight back on the "line of the putt" and then — with the dominant hand (i.e. right for right-handed) — move the putterhead straight forward and straight through the ball, all on the same "line of the putt".
The putter head remains "square" to the line-of-the-putt throughout the stroke. This happens because of the hand/forearm position of the recommended MACRO set-up and the patented physical features (reducing oval shape and forward shaft offset) of the MACRO Putter Grip.
No other putter grip keeps the club head completely "square" throughout the putting stroke without hand and forearm contortion.