i start with a bold circle and then alternate one dot on one side, one on the other to the left or right of the original til i've gone around the entire circle. next, fill in spaces between dots to cover the circle entirely. build away from the circle of dots, placing dots that do not touch the circle outside the circle. finally, use smaller dots to show "radiation" from the focal point.
forgive the rough drawing. still getting used to my bamboo.