Consider what could be accomplished in public transit if individuals were equipped with a simple pulley and harness. Suppose you could go into an authorized dealer, show them your license, and for a few dollars purchase a government inspected pulley and harness - something you could carry in a briefcase, knapsack, or purse.
The pulley-harness unit is compact and light. The pulley has two small rollers and is equipped with a brake for slowing and stopping....
This very simple idea, if you explore it, becomes more and more fascinating.
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