Figure 8 is the sign for infinity. You can think of it as a combination of two circles.
Before you click on the video below, can you see the taichi symbol as two warped water drops?
Can you see how it is morph into other concepts?
Do you see how the wings flap?
The following is not directly related and yet is.
Exercise
From the above videos, it looks like dots / lines / squares / circles / water drop / infinity symbol / taichi symbol all related. How is it related to our martial arts? How do you apply it?
Figure 8s