Much like a carpet, artificial grass has a pile direction. This means that each fiber of grass has the tendency to point in one direction.
If you don’t match the pile directions on your pieces of artificial grass, you’ll end up with not just a subtle zigzag, there will also be much less subtle alternating gradients in the color.
To avoid this problem, install each piece so that the pile is facing towards your house. This way, you can be sure they all face the same way and the grass will look its best when viewed from your home.