MD5 collision visualised

On this webpage, there's an illustration showing of the evolution of the internal state in an MD5 hash collision. I really need to sit down at some point and make the effort to understand the technical details of the MD5 collision attack. Here's the reference:

• Xiaoyun Wang and Hongbo Yu, How to Break MD5 and Other Hash Functions, EUROCRYPT 2005 [7].
  

Tags: MD5 , Cryptography