The genius in his design is that the coils are actually etched into the PCB, completely taking the human effort out of the equation. Made up of 6 mil traces with 6 mil separation, the PCB coil ...

A stacked buck-capacitor ... more coils. Benefits of Stacked vs. Side-by-Side Coils Stacked coils hold an advantage over side-by-side coils because they have a smaller footprint on the PCB.