Chord Progression Multiplication

With the help of abstract algebra, certain chord progressions can undergo multiplication. This website provides a calculator to multiply custom chord progressions below and an interactive catalog on the Catalog page to multiply chord progressions found in music. To read more about the mathematical reasoning behind the multiplication idea, visit the Approach page.

Rules

When multiplying two chord progressions, there are a few rules to follow.

In a progression, no chord may appear more than once.
To avoid an output equal to the input, both progressions should share at least one chord.

To Note:

This program multiplies progressions in the same direction as function compositions like f(g(x)): right to left.
Multiplication from left to right is equivalent to g(f(x)), which the program's output also includes.

Calculator

Enter two chord progressions below, where chords are separated by a single space.

Output: