Woah Hypoguy! That's very odd eh? I've only heard of off-white stones a few times before. Don't quite know what to make of them. And did you say polygons? Gallstones (as opposed to liver stones ) are supposed to be an interesting shape like that...hmmmmmmm! Were they off-white all the way through? Did they look basically the same as your other stones from previous flushes - only the colour was different?
That's pretty interesting Hypoguy...did you do anything different this time?