Here’s another figure/ground effect.  A saint becomes a balustrade!  Almost any vertical figure whose profile is not too wiggly can be used for this illusion.  Below is a different version of it.  It’s a little more puzzling, because both saint and balusters, when seen as figure at the ends of the picture, have the same starry sky as background.  That’s done by making sure that when saint or balusters are seen as background near the ends of the row, they blur into the same starry night sky.

These illusions are of course just variants of the famous faces/vase illusion.

For an earlier post on figure/ground effects see the one on objects, spaces and outlines.  I also did cartoon style pictures (with commentaries) trying out different figure ground effects for my optical illusion cartoon story.  There’s one that scrambles space, (scroll down to the second picture).  Or check out this introduction to figure/ground effects generally, on a brilliant site, authoritative but fun.