Thought of this while driving home from the lofters. As if we need one more analogy for relativistic speed limits, but here goes... Q: How is c a speed limit? Why can't we just go a little faster and exceed it? A: Behold an analogy as to how geometry can limit movement, no matter how fast you go. Think of one of those swing merry-go-rounds at the fair. Here's a small one: (Those are Indestructible High-G Robot Child-Androids.) The pole is exactly 2.99792458 metres tall, a value we will call p. The Propulsion unit of the merry-go-round has complete freedom to increase or decrease the device's revolutions, but has no ability to directly affect its altitude. As the IHGRCAs increase their revolutions, their altitude will approach p. At 100revs, they will reach .99p. At 200revs, they will reach .999p. At 300revs, they will reach .9999p. They can continually increase their revs without bound, yet their altitude will never reach p, merely asymptotically approach p. And no amount of revs will ever allow them to exceed p; the attempt is obviously preposterous. So the limit of their altitude is dictated, not by some retarding factor, or by some inability to put more effort into it, but by the mere geometry between revs and altitude. Clearly, this does not explain the physics of c as a speed limit - there will be more questions - but what it does do is get relativity students to start thinking about spacetime as a geometry. A big step, IMHO.