18th Nov: We've switched servers and will be updating the old code over the next couple months, meaning that several things might break. Please report issues here.
A chord progression consisting of the following: I vi IV V. If that didn't make sense to you, try playing the following chords: C major, A minor, F major, G major. Repeat. Also known as the "50s progression". Possibly most famously occuring in the song "Heart and Soul", which starred for years on the TV commercials of Quaker Oats. In Finnish language, this progression is known as Aku Ankka -kierto (Donald Duck progression). Closely related to the Humoresque Progression, which instead has I at the end.