In the penultimate episode of Puella Magi Madoka Magica, we briefly see this image, possibly formed by the ice in a glass of alcohol when Madoka's mother is at the bar with Madoka's teacher. (This image comes right before a "break" from that scene before the episode shifts back to Homura's room, so it's hard to tell. While initially that seemed like a reasonable interpretation to me, in retrospect, the two "blades" here suggest that this isn't the case, and that the image is superimposed onto something else.)
This clearly seems to be one of the more famous details from Michelangelo's The Creation of Adam, which is on the Sistine Chapel ceiling:
What is the significance of this image in the context of the anime series? With other references in the series, there's often a clearer connection (e.g. to Goethe's Faust) but here it doesn't seem as obvious, and the only interpretation I can think of is related to Madoka becoming some sort of god, but even so, using this specific reference doesn't seem to make much sense here.