Hidden Faces

After doing a project with NABBI-pearls, I had several protective sheets from PhotoPearls adhesive sheets. Out of boredom and nostalgia, I cut the protective sheets into weird shapes, glued them onto an A4-paper and coloured the spaces with a pen. Everytime I look at the result, I see funny faces. It doesn't matter if I hold it upside-down, more faces appear before my eyes, like Picasso himself hid them there.

How many weird faces can you see? Can you see any at all? Only half of those I showed this to could see something.