Easy. Pick a fix and fly over it then time your outbound leg. So if I fly over the fix from the south and fly outbound from it on the 360 radial, I subtract 30 degrees from that and make a left turn to fly back inbound on the 330 radial and when I recross the fix fly the same length of time on the 150 outbound radial. Again, subtract 30 and make a left turn to fly inbound on the 120 radial and outbound on the 300 radial. Then in on the 270, out on the 90. Use the same time for each outbound leg. After 12 left turns I exit on a 360 course again, leaving behind a 12 petal flower (360/30 equals 12 'petals').