This is a design based on Tai's Crest of Courage from Digimon. The Crests are symbols of each character's dominant ability (even though they might not see it at first - Matt, anyone?) and help provide the boost that each respective Digimon needs to evolve to a higher state. I always thought the Crests were worth a bit of study.
These Crest drawings are years old now, but I thought some Digimon fans might still be interested in them. Around the time I drew these I was also immersed in a Celtic artbook, so I tried to make that the theme. The knots you see on here don't really follow any rules and would probably make an accomplished celtic artist wince in pain, but hey, I was young :)