Bob Dylan may have contributed to 420's popular use with his song, but he did not create it. He wrote a song that contains no direct reference to 420 that just happens to be about marijuana. “Rainy Day Woman #12 & 35” may be a song you listen to on 420, but it is not the origin of 420. If you start applying arithmetic to every numeric reference in marijuana-themed songs, you’ll find others that create a combination of 4, 2, and 0. “Rainy Day Women’s #12 & 35” multiplication association to 420 is pure coincidence.