site-setosa-markov-chains
http://setosa.io/blog/2014/07/26/markov-chains/index.html
http://thexbar.me/2014/10/24/raddecay/
From the comments: The most important conceptual point regarding Markov chains is that they are memoryless: future states depend only on the current state and not a previous history of which states have been visited ^memoryless