Emperor Yu had seen the divine turtle before, but as a pattern in the stars, never this close. Every night, right before he went to bed, Emperor Yu would look out his bedroom window and see the turtle in the night sky. The emperor knew the Lo River story and believed that the turtle was a symbol of good luck. Just before he went to sleep the emperor would look at the turtle to ensure continued good luck. Now it was right before the emperor, swimming slowly at the river's edge.
Wanting to get a better look at the magic turtle, the emperor took one step closer. The turtle didn't notice the emperor and continued to move its legs slowly in the clear water. There was no mistaking the divine animal, for Emperor Yu had watched it with great care for many years. The emperor was familiar with the shape of the creature, but the detail of the shell that Emperor Yu now saw was new to him.
A turtle's hard back is half of the tough house that protects its body from enemies. The roof of this house looks like puzzle pieces glued together to form two circles around a rectangle. Emperor Yu looked long at these shapes on the turtle's back and noticed a pattern of dots etched on them.
As the river became dark, Emperor Yu lost sight of the turtle and started for home. Walking slowly, the emperor thought about the different numbers and their positions one to another.