The viper's nest of cables under your desk might be bad now, but imagine how much worse it'd be if your desktop spun around every few seconds, independently of the legs. That's the cable management issue faced by industrial robots, which have multiple parts that often rotate along different axes.
One company with a solution is Igus, a Germany-based manufacturer of industrial machine parts. A sub-specialty of theirs is "Energy Chain Systems" made from plastic components, designed to twist and bend while preventing the cables within from becoming kinked and abraded. Here's a guy who works at Igus named Harold, and he's very excited to show you these chains:
The craziest-looking out of all of them is the one that coils in multiple directions like some kind of Escher drawing. Called the TwisterBand Chain, it's capable of rotating 540 degrees. Here's a closer look:
The reason Igus manufactures the bulk of their products out of plastic, rather than metal, is that it's actually superior in these types of applications: Unlike metal they require no lubrication, which cuts back on maintenance; they're better able to handle friction, so last longer than metal parts; and of course, the material costs are cheaper.