First of all, I'm still around! Keep posted for more music education. Now then... Students,
Now you know a little about the 12 bar blues progression thanks to Chuck Berry and his legendary 1958 song "Johnny B. Goode", made famous (again) by the 1985 movie Back to the Future.
The opening guitar riff is taken note for note from the horn section of the song Ain't That Just Like a Woman from Louis Jordan (1946).
The song is so important in music in rock and roll history that it was put on the Voyager 1 Golden Record (by direction of the amazing Carl Sagan) and launched into space. (Voyager 1 is still traveling at 17 kilometers per second and is 19,571,030,000 kilometers from the Earth (yes, that's 19.5 billion).
Just remember I - IV - V - I for next class.