In short - a Newton's cradle where the ejected element swings around over the top to strike the first element. Ie if you number the elements from left to right 1234, when 4 strikes 3, 1 is ejected, swings over the top and strikes 4, ejecting 2, etc etc ad nauseum.
I've looked but not found an example of this.
Requires a lateral axle (so they are all concentric about a common axle) rather than a longitudinal one, and therefore the elements won't lie naturally in a straight line but will follow the curve of their radii. It will be interesting to see how good the force transfer is along a curved path between the elements rather than a straight one like most NC's.
The yoke for each element would be a two cords forming a Vee, and you simply have successive elements having a more acute Vee so that the cords do not interfere with each other.
Starting this thing could be a bugger, but that'd be half the fun. Also thinking that because the elements will at rest sit in a shallow arc at the bottom, if they're spheres they might slide past each other. So maybe they're better off as short rods with slightly chamfered ends rather than spheres.
Executive upgrade - use a small linear accelerator somewhere along the arc of travel to add a small impulse that's callibrated to exactly counteract the frictional losses. This thinng will have to operate fairly energetically as each element needs sufficient velocity to smoothly travel over the top without slackening it's yoke - and so your air friction losses will be relatively high. Another option is to have rigid yokes on bearings so that you only need just enough velocity to "go over the top" which, when I think about it, would have a cool speed up-slow down effect that would look much cooler than the original concept.-- Custardguts, Mar 08 2012 Clackers -- Old and new http://www.skoolday...ies/toys/ty1427.htmFun and sissy. [baconbrain, Mar 09 2012] New Clackers on video http://www.youtube....watch?v=gPyBAWe-OqwTwo spheres on rigid yokes. (After about 20 videos of the stringed kind.) [baconbrain, Mar 09 2012] This I like.
The "over the top" move might be difficult (will the ball have enough momentum to keep the string taut at the top of its arc?).
Suggested solution: instead of strings, use rigid rods.
[+]-- MaxwellBuchanan, Mar 08 2012 [Max] -yes I covered that issue in the final paragraph. I figure that's really two different configurations - one is a highspeed model operating at >1g which can have nonrigid yokes, the other has rigid yokes and can operate down to as low as just above stall.-- Custardguts, Mar 08 2012 Alternate name: "Orbital Mechanics". [+] I'd like to see one of these.-- AusCan531, Mar 08 2012 It must be built.-- 2 fries shy of a happy meal, Mar 09 2012 There's a kids toy that has two balls, each on two struts, on a common axis which extends from a handle. Kids can whip the balls around, alternating after each impact, as a two-balled Newtons cradle, or bounce them up and down to hit at top and bottom.
It's the safe version of what we had when I was a kid--Clackers--which was two balls, one on each end of a string, and in the middle one ring to hold them by. It was loud and dangerous and fun.
<-- Links.-- baconbrain, Mar 09 2012 <adds Clackers to list of things to get>
I remember those... like numchucks but more dangerous.-- FlyingToaster, Mar 09 2012 I remember bruises up to my armpit. They also had the tendency to shatter. Good fun though.-- AusCan531, Mar 09 2012 random, halfbakery