Here I would like to add a few more serious techniques for finding Pi, just in case you find yourself stranded on a desert island without a computer or a copy of

Of course if the island is perfectly circular the problem is trivial.

- Now I know a number. (only 4 decimal places)
- May I draw a circle? (only 4 decimal places)
- Now I must a while endeavour to reckon right the ratio. (10 decimal places)
- Sir. I send a story excelling

in sacred truth and rigid spelling.

Numerical sprites elucidate

for me the lesson's full weight.

If nature gain

not you complain

tho Dr Johnson fulminate. (30 decimal places)

- Paint a spot on the edge of a large circular wheel. Spin the wheel and measure the number of rotations per second. Next run with the wheel and let someone observe from the side the sinusoidal patern made by the spot and measure its angular frequency. Find pi by dividing.
- Find a black body, measure its spectrum and fit
it to Planck's distribution. This will give you Planck's
constant
**h**. Find two superconductors and a nonsuperconductor, make a Josephson junction and apply a DC field. Measuring the frequency of the oscillatory supercurrent will allow one to measure**h-bar**which is**h**time 2 pi. Division gives 2 pi.

(It has been suggested that by using the known value of pi this experiment becomes a physical measurement of**2**.)

- S. Ramanujan reports that family deities can inspire you to know pi to hundreds of decimal places.