OPENGL bitmap text (using glutBitmapCharacter) & stroke text (using glutStrokeCharacter)
http://dis.dankook.ac.kr/lectures/cg07/entry/OPENGL-bitmap-stroke-text

Sierpinski gasket
http://dis.dankook.ac.kr/lectures/cg07/entry/시어핀스키-가스켓Sierpinski-gasket