My inspiration was the color plate by John R. Neill, found in The Emerald City of Oz. I did make some changes in the arrangement of the windows and the top of the house, but otherwise attempted to stay true to Neill's concept.
The final touch was to add Oz characters, taken from the Oz Toy Book, reduced in size and glittered. Add a bag of candy to the interior of each one and voila! A centerpiece!