Sorry for the sidetrack, but that is such an incredibly beautiful object, with those delicate etched hyperbolae. So much skill and craft went into making it and

Sorry for the sidetrack, but that is such an incredibly beautiful object, with those delicate etched hyperbolae. So much skill and craft went into making it and you can see that it is a superbly-designed practical tool that was well-used. It's quite humbling to see things like that.