palindrome, retrograde and paradox

In this canon, I use the same duration row as I did for Monday's. This time I used only the original (O) and inversion (I) for the upper part. In this way I could make a canon in retrograde by using RI followed by R in the lower part.

If I had kept the palindromic structure of Monday's canon, I wouldn't have been able to make a canon in retrograde...or would I?

Since a palindrome is its own retrograde, perhaps every simple canon on a palindrome is also a retrograde canon.

This puts me in mind of Messiaen's non-retrogradable rhythms. These are simply rhythms that read the same left to right as they do right to left -- in other words palindromes. They are non-retrogradable because they are their own retrograde.

A nice little paradox...

(click on image to enlarge)