[ucuttxtc] Mersenne sculpture

Create a collection of physical objects recording, representing, celebrating the discovered Mersenne primes so far.

Distinct objects is better than a single fixed object (e.g., a plaque allowing for new entries to be added at the end) because new Mersenne primes could be discovered in the gaps between currently known ones.

Easiest for each prime is an object with (at least) one linear dimension proportional to the log of exponent, onto which the exponent is inscribed (perhaps several times​ on different sides, backwards and forwards, for redundancy).