

Inverse graphing calculator - anigbrowl
http://www.xamuel.com/inverse-graphing-calculator.php?phrase=Hello+HN

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rcfox
How about a copy-able version of the equations so that we can test them to see
if they actually work?

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rubidium
Copy image location of the img gives you the equation in TeX.

Then you can use ToExpression[...] in Mathematica to try and graph it.

I haven't tried it myself, but I assume that should work.

[http://reference.wolfram.com/mathematica/tutorial/Generating...](http://reference.wolfram.com/mathematica/tutorial/GeneratingAndImportingTeX.html)

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rcfox
Hm, Wolfram|Alpha doesn't like that function, and I don't have access to a
real instance of Mathematica...

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gjm11
Not so good.

First minor hurdle: Mma treats backslashes in strings as escapes. But even
after doubling them all, I still get "Could not parse [BLAH] as Mathematica
input". A bit of experimenting suggests that Mma doesn't like \cdot, so I
removed those. I took out the explicit linebreaks at the same time.

Now Mma is able to parse the TeX. So far as I can tell from a quick glance,
it's understood it OK. Unfortunately, I've had no success in getting it to
plot it. RegionPlot[...==0...] produces nothing. ContourPlot[...==0,...]
produces nothing. Without the ==0, unsurprisingly, no contour Mma chooses to
draw looks at all appropriate. The trouble is that (1) the function is varying
so damn fast in the relevant region and (2) those zero contours are all
"valley-bottoms", and there's not much way for Mma to know they're there at
all. Even giving unreasonably large values for WorkingPrecision,PlotPoints and
MaxRecursion doesn't help, unless you consider running the Mathematica kernel
out of memory "helping".

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revorad
This is clever. But surely, 'l' and 'o' should be simpler.

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bboylan
Someone make a self printing equation.

It would totally make my day.

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giu
Here you go: [http://en.wikipedia.org/wiki/Tuppers_self-
referential_formul...](http://en.wikipedia.org/wiki/Tuppers_self-
referential_formula)

I hope your day _is made_ now :)

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gjm11
Nope. That's an arbitrary-thing-printing equation, controlled by a parameter
that you have to set to a Very Large Number to make it display anything
interesting. The Very Large Number is not part of what the formula displays.
To get a genuinely self-displaying formula you'd need to throw in some
Goedel/Quine tricksiness.

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roundsquare
Very neat.

I'm guessing you have a function for each letter and you add a shift depending
on where it is in the phrase? Or are you creating the formulas on the fly?

If its being created dynamically, you could probably find a cool way to do
this for arbitrarily drawn pictures.

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JBiserkov
Why does every "string" end in (y^2 - 6y +8 + sqrt(y^4 - 12y^3 + 52y^2 - 96y +
64))^2 ?!?

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merraksh
It's a rather complicated way to ensure that all points have y coordinate
between 2 and 4, thus cutting all lines that would extend out of the
"writable" two squares.

That expression equals zero if and only if 2<=y<=4.

(edit) If you try "L", the formula contains a product member (x-2) that would
produce a vertical line whose points all have x=2, containing the vertical
segment of "L". The final string excludes that.

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cracki
how about an "inverse" graphing calc that takes an arbitrary line drawing and
gives me a "nice-looking" equation and not just the vectorized representation?

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hristov
Great now I can just generate the equations for "suck my cock" and put them on
a t-shirt. And then I will be insulting everyone I meet without them even
knowing.

