This is a photogram of tadpoles, using flash on coloured photographic paper.
I really like this piece because it shows the silhouette of each tadpole in detail, and because they're so clumped together into tiny spaces, it makes you search for detail, and leads your eye around the edge of the jar, noticing different aspects of the photogram each time. I also like how you can define which tadpole is older than the other because of all the detail you can see. I think it would be interesting to try something similar, but instead of using tadpoles, using frogspawn, to see how detailed a photogram I could get of something so tiny. 
Looking at this photogram brought back memories of when I was a little kid and I used to play with my cousin and try and catch tadpoles, which I is why this photogram has such an impact on most people who see it, because its nostalgic, and makes you see things clearer than as if they were in a memory.