The diagram at left shows the course sailed by one boat in a typical LMYRA "island" race. A windward buoy was used to establish a first leg directly upwind from the starting line, then the course ran downwind through the "gate" (same marks as ends of the start finish line) to Doolittle island. After rounding Doolittle island to starboard (on the starboard side of the racing boat), the race continued upwind to the W mark again, then back downwind to the finish line.
On the first upwind leg, this competitor tacked four times. The boat's path sometimes curved as the wind shifted slightly to the north or to the east, creating "headers" or "lifts" depending on which tack the boat was on. Lifts allowed the boat to sail a more-desirable course (closer towards the windward mark), headers forced it to sail a less-desirable course (veered away from the windward mark).
The downwind legs are more straight because the boat could sail almost directly towards the gate, and then through the gate and towards Doolittle island. After rounding the island, one can see that the track of the 2nd beat (2nd upwind leg) was often-unsteady as the wind shifted back and forth about 10 degrees. One of the headers and one of the lifts are indicated on the diagram.