What is the most efficient?

Spiral directions could be as efficient way but doesn't give good look for the lawn afterwards. By starting first a straight line would be so wonderful. Straight line method could be as efficient too as well as kept the lawn in nice and well arrange. Start mowing by making two parallel straight line with an approximate distance of about 5 laps width of your mower machine. Then proceed mowing on the adjacent side of the line then on the same side of the another line in every way/trip. When done on one area, repeat procedure on the next area.