Hello math-funsters, After seeing some of the desires expressed by xkcd forum members, I decided to implement an online server version of my RIES program [1] at the address: http://www.mrob.com/pub/ries/index.html (or simply mrob.com/ries ) It's a pretty basic service, mainly due to the constraints of the server. But it's still kind of fun and certainly adequate for a lot of the recreational maths that the program was intended for, like the approximations in last Wednesday's xkcd [2]. For example, 1.234321 ~ Sqrt[Pi-Phi]. I've bashed on it over the weekend, and gotten a fair amount of traffic from around the world. I think I have it working pretty well now but it would be nice to see what some more math-oriented folks think. So go ahead and throw a few numbers at ORIES. - Robert [1] (RIES is a semi-silly acronym for "RILYBOT Inverse Equation Solver"; the program source code has been online since 2000) [2] xkcd.com/1047/ "Approximations", is full of examples of just the sort of thing my program is "meant for". Although I and RIES are mentioned, Randall Munroe and I did not communicate about it beforehand and it came as a complete surprise to me. Munroe clearly likes his numbers almost as much as I do. (See for example xkcd's 221, 798, 759, 718, and 715) -- Robert Munafo -- mrob.com Follow me at: gplus.to/mrob - fb.com/mrob27 - twitter.com/mrob_27 - mrob27.wordpress.com - youtube.com/user/mrob143 - rilybot.blogspot.com