And a PNG version too: https://news.ycombinator.com/item?id=32956964
But no one has made an exclusively plaintext (ASCII) MD5-quine yet, and I suspect doing so may be impossible given the characteristics of collision blocks.
1. a document containing "1", whose hash begins with "1"
2. a document containing "12", whose hash begins with "12"
3. a document containing "123", whose hash begins with "123"
#1 is certain to exist. #2 exists, but would take 16x as long to brute force. #3 would take 16x longer again. If this pattern doesn't continue until 2^128, where would it stop, and why?
All hashes can be brute forced this way, even secure ones SHA-2. Its security relies on the fact that the earth doesn't contain enough computing power to execute a brute force attack within the universe's lifetime.
Therein lies the problem.
Also the fact that it would need to be constrained to 7-bit ASCII only, and on top of that be "valid" in its natural language. It's a neat trick to make two documents look completely different with the same hash, but looking at the techniques which are required, they all rely on a binary file format and copious amounts of data which are effectively "hidden" --- all of which do not apply to a text file.
The problem is that we currently don't know how find it more efficiently than with exhaustive search, AFAIK.
Edit: previously on HN: https://news.ycombinator.com/item?id=614079