There was another quilt posted on here recently with this same pattern, done in blacks, whites, and brights. What a cute pattern! On that thread, it said the pattern "is in September/October 2005 of Fons and Porter under the "Witches Workshop" spread. The tutorial is also on the Fons and Porter website." Haven't checked out my old mags, but I should have this.
Are you planning on using using these 2 blocks or an assortment of colors? This looks great! So glad you posted this and I stumbled upon it!