Each of the three sides of the pavilion at San Stae, as well as the Ukrainian pavilion near La Fenice, are details, in painted eggs, of the Van Eyck brothers' large Ghent altarpiece. Some of the eggs are covered in decorative motifs, many others with figures, symbols or brand names. According to one source I found online (http://www.fundgp.com/en/media/news/190/) different people were asked to paint their idea of sin on the eggs. One egg per person? I don't know. But I suppose that might explain some (but only some) of the images you may find in the more detailed pics below if you click on them and look closely enough. Though if this is the case I'm dismayed by how many people still seem to equate the nude female figure with "sin". Perhaps just wishful thinking on their part?
In any case, this would explain only partly who painted some of the eggs, and with what in mind. Another panel, the one which depicts a detail of Mary's face, is composed of eggs painted in floral motifs and has nothing to do with any notions of sin so far as I can tell. Botanists or gardeners or disciples of John Ruskin may correct me on this.
There's more to find out about this, and no doubt more that could be written, but better to show you some images--and here is the artist's website: http://www.mas-art.com/home
|Detail of Mary's mouth|
|Detail of the detail of the crown of the Ghent altarpiece|
You can see images of the central part of Mas's massive work, as displayed in the Church of San Fantin, here: