Take the number 15, multiply it by itself, and you have 225; now
multiply 225 by itself, then multiply that product by itself, and
so on until 15 products have been multiplied by themselves in turn.
The final product called for contains 38,539 figures (the first of
which is 1412). Allowing three figures to an inch, the answer would
be over 1070 feet long. To perform the operation would require about
50,000,000 figures. If they can be made at the rate of 100 a minute,
a person working 10 hours a day for 300 days in each year would be 28
years on the job.