# 26: Fourier

Fourier |

Title text: That cat has some serious periodic components |

## Explanation

A Fourier transform is a mathematical function often used in physics and engineering.

## Transcript

- [Person talks on phone. Cat with many sharp points looks on.]
- Person on phone: Hi, Dr. Elizabeth? Yeah, uh ... I accidentally took the Fourier transform of my cat ...
- Cat: Meow!

## Trivia

- Original comments from Randall: "I like the idea of a graph meowing. Also, that cat has a lot of periodic components."
- This is the twenty-seventh comic originally posted to livejournal. The previous was 25: Barrel - Part 4. The next was 27: Meat Cereals.

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# Discussion

Isn't the cat also imaginary because its Fourier transform isn't symmetric?

I feel like there's another joke in that his cat is "imaginary" or has complex components.

Shdwdrgn (talk) 06:33, 8 October 2014 (UTC)shdwdrgn

Might this also be a Garfield joke? Garfield's veterinarian is named Liz. Although Garfield, being roughly a three-dimensional ovoid, would probably end up with a much different looking Fourier transform than what is depicted here.

--199.27.130.246 21:26, 9 October 2014 (UTC)

I think the transform may be of the movements of various parts of the cat. Cats tend to move their ears and heads a lot, and other parts, less so. What tipped me off is the spike at the tip of the tail. Cats typically twitch the very tip of their tail in a rhythmic fashion. 108.162.216.192 21:52, 2 March 2015 (UTC)

Coincidentially, the Fourier transform of a cat was used in a 2003 paper on the so-called phase problem in protein crystallography (figure 3) to illustrate the relevance of phase and amplitude information. See http://journals.iucr.org/d/issues/2003/11/00/ba5050/index.html and http://journals.iucr.org/d/issues/2003/11/00/ba5050/ba5050fig3.html