Knots work because of wrapping friction. That kind of friction depends on the angle of contact.

The angle of contact is more than 6.28 whenever a rope or chain is passed once completely around an object (making a complete circle) because the equivalent to the 360 degrees of a circle is 2 radians. The angle is the power that the base of natural logarithms e is raised to in order to get the force-amplification-factor.

Suppose a one pound pull is exerted at the person-end of the chain. If the chain was wrapped three times around an immovable post, that single pound balances the equivalent of

exp 18.84 = 1.52093 x 10^8,

or well over one hundred million pounds of force.

One explanation of computing power derives from its use of exponents in mathematics. Repetitive computations are akin to small steps that can tackle big problems. This is illustrated by the person holding back a tank, or a single paper clip holding a much heavier assembly of metal parts.