My variation (as most of mine are) is a variant because it went a bit wrong!
I have tons of old music in the house and I don't play half of it so I tried to make a coaster based on the Eco Coaster. Music is pretty heavy weight paper and I couldn't get them as thin as I would have liked but hey.. still looks alright!
I backed it with the cover of the music I used.
(Wish I'd measured those 45 degree angles before cutting them!)