... points^2.1

It is for a good reason that the PESSL Spectral Method example we went through in our previous lecture, P573, asked for 7 harmonics in each direction, because $2\times7 + 2 = 16 = 2^4$, which is a good number for FFT.

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... follows^3.1

There is an error in the formula for c in the ``Numerical Recipes''. But the code is fine. You can easily spot the error if you compare the formula with the code actually - assuming that you don't quite remember what it should be.

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