"Tae Kook" is the Korean flag. "Tae Kook" means "the origin of all things in the universe". The circle in the centre of the flag is divided into portions of red and blue by a horizontal 'S'.
These red and blue portions symbolise the 'Um and Yang' theory of eternal duality which exists within nature (e.g., heaven and earth, light and darkness; hot and cold; being and not being). In science, this theory can be represented with the symbols '+' and '-'. These dualities exist as a principle of the universe.