Start with the letters in the top left circle, and move around the other circles in a clockwise direction. Letters advance through the alphabet 6 letters at a time, with the relative positions of each letter moving one place clockwise each time.
Start at the top to the left hand triangle, and work across the whole diagram in horizontal lines from left to right, top to bottom. Letters are written in alphabetic sequence, skipping 3 letters each time.
In each star, start with the letter in the lower left hand point, and move around the other points in a clockwise direction. Letters advance through the alphabet in steps of 6 for the left hand star, 7 for the one in the centre, and 8 for the right hand star.