Yin and Yang

A birthday present for our karate teacher, who is a great person and whom I respect. Not too long ago, he told me he wouldn't mind at all if I drew some picture for our dojo, if I had some time . And because it not only sounded like a good idea, but also because I feel like I owe him, I thought of this. And now some explanation of the motif:

In the middle is a logo of the dojo - Shinzato dojo in Prague. In the center of the logo on a white background is the symbol of the style of "our" karate - the Goju ryu. "Goju ryu" can be translated as "hard-soft style" that emphasizes both the inner and outer strength. The name of the style comes from the third of the eight precepts that are the essence of the martial arts, written in the scroll called Bubishi: "The way of inhaling and exhaling is hardness and softness." And the style indeed concentrates a lot on the breathing, because it's important to develop the external as well as the internal strength.
The symbol of the style means the same. The circle-like thing represents the heavens and the soft, while the rectangular part in the very center stands for the earth and the hard. 
Around it in the dojo logo is something similar - two forces merging together or pushing one other. Like yin and yang. I chose to continue this pattern and draw two tigers jumping in sync as the two opposing forces that are both equally strong, chasing each other.
Tiger is one of the five animals connected to (especially chinese) martial arts (where the origin of karate lies, too). Tiger's attributes are courage, aggressivity and power, it probably has to do with the flow of qi (the energy), too, and is strong enough to shake the earth. It's one of the two strongest animals in chinese astrology together with the dragon.

Sorry for the load of text, but i felt like explaining the meaning of what I tried to draw. 

A slightly bigger than A4 scratchboard.