How to Build a Human by Eleanor Lutz
I made this using 44 animations that are 9 frames each. That's 396 sketches total - probably the most complicated GIF I've made so far. I am a little sad that I wasn't able to show size properly though. For example, the 24 week fetus is about 40 times heavier than a 12 week fetus (but you can't tell that from this drawing).