I think we did that in the when I was in the "Boyscouts" LOL!
I tried that when I was 4 with my sister, dunno if it was the cups or the wires, we tried 4 different cups and 3 different wires and differend lenghts, didnt work. I I always have been ambitious and furious so I always start big and have a quit hard time giving up... We build fords and huts in our bedrooms with whatever we could find (loads of fights over who gets what) and then we wanted intercom systems down the stairs up to the front door... in the end we tried it on a 2 meter lenght. Unlucky for my parrents they where not allowed to clean it up (yes they had to because with the mess I made back then you need half a day to clean it up and in no way was that possible on your own) we kept it for a week and "pretended" it worked. Still managed to confused the shit out of our neigbours with 4 cups (me, my sister, master bedroom and I believe the cat but im not sure "logic") hanging at the front door...
I just realised, my parrents made the joke that it was the russians, now I understand that joke... (russian woodpecker)
Another fun thing, and I'm wondering if other members had similair things, 3 weeks a year (2 weeks in summer and the week before christmas) me and my sister where allowed to cover the entire house in all of our toys exept the master bedroom, the kitchen and my dads office. Trains from the living room to the dining table via the front door, lego buildings boats and cars everywhere all of the maistro and other car models covering the floor, the fleischman racetrack though everything, in short, the entire house would be like our little miniworld.
we had a lot of toys since my parrents are furious on thriftstores and flea markets, we bought toys and lego in bulk for less than a buck, queensday (now kingsday) traditionaly has a notoriously big flea market tradition, and as family tradition we still go and in the end make up a list of what we bought and saved by not buying it of marktplaats (dutch craighslist but more organised). 80% of the attic is still filled with toys. It would take up to 5 days to clean all of that up with both my parrents, sometimes my grandma, me and my sister...
Also the reason my parrents did not look forward to picking us up after a vacation with my grandparrents. My grandparents would allow everything as long as they dont have to clean it up and it needed to be cleaned up before we left. That meant my parrents would come to pick us up and they had to work realy hard to clean everything up. Luckaly for them my grandparrents did not have much toys but before we left there was always the discussion that next time they should not alow us to make a mess again... Good luck doing that with grandparrents...