I'd welcome input on an essay on Polya's urn model that I'll be posting at Mathematical Enchantments on Saturday. (It's still a bit rough; I plan to re-do all the figures as well as the embedded video, and if time permits I'll add some extra video content as well.) See https://mathenchant.wordpress.com/?p=203&shareadraft=561bd3e655f2b Title: Pólya's Urn Beginning: "Life has a way of magnifying chance effects. Bad luck in romance can make you embittered and wary, making you less attractive to potential partners. If the post office delays delivery of a big check you were counting on, so that a check you wrote ends up bouncing, you'll instantly get charged overdraft..." I'd especially welcome references and links to accessible articles, applets, and apps that are relevant to the Polya urn process, or to what I call the "non-Polya urn process" (which is just a nonce-name for generating a binomial random variable from a Bernoulli process), or to quasi-random simulation of random processes via chip-firing. The best way to reply is via email (directly to me or, if you think your remarks will be of general interest, to math-fun). If you do use the feedback link at Wordpress, keep in mind that I have no way of knowing who you are unless you sign your feedback. I prefer non-anonymous comments, so that if I have follow-up questions I know whom to ask. (Did Martin Gardner ever write about the Polya urn model? If so, I'd like to include a reference. But I just searched the CD containing all of Gardner's columns and couldn't find anything.) Jim Propp