It will get there where you recognize what you are looking for. A specific thing in the piece that will stand out. Like your stripe. Notice how it reacts to where it it. If it is a bit do you want the bit in the venter. If it is all along the edge. Do you want it to run the outside. After the first 100 blocks or so it gets easier. Just kidding. It takes as long as it takes. My mom when she was helping me with one did it til the end. She was growling at me as I just picked them up took one look and could pretty much tell which way I wanted it to go. And really, there is no wrong way.