Reddit's Smsilton took this incredible 60mm macro shot of an iconic MC Escher painting being refracted through a drop of falling water, and documented the process:
Yeah I used the Canon 60mm macro f/2.8. I shot at ISO 640 and 1/250. It took about 150ish shots to get that one, ~2 hours. The hardest part was focusing, in the set up picture I posted in the first comment you can see a piece of string above the eye dropper. I would let that hang down off the eye dropper and focus on that, then move it and squeeze the dropper and the shutter at almost the same time. I have like 30ish more pictures with the drop clearly in the shot but the sketch behind it isn't in focus, this was the clearest one I got.