I thought my fellow Aussies - especially the sandgropers - would like to see a couple of our iconic waterfowl - the black swans.
Unfortunately, I can't show you the image here just yet - I don't have ten posts showing in the forum. But you can see it at Flickr, if you open the folder photos/yuyiya then choose the only non-human subject of the two photos there.
Just to make sure you can find it, it's photo number 3475241417/ in my folder. (Don't forget to put slashes / between the pieces of the filename.)
Hope it's worth the effort ...!
Now, tell me if you can - what is the illusion here?