I've got a practical experiment for you to try out.
1) Put a long (30cm for example) thin chain (the smaller the links the better) on a very steep ramp which it can slide down easily and watch it slide down.
2) Repeat, this time placing 5mm of the chain over the top of the ramp, observe and record results.
3) Repeat with 1cm over the top of the ramp.
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