ONE-LINERS: Grow a picture or video from a single line of C or Python code

Does your one-liner picture look wrong?

I get a text picture that says there's an error but it's not very helpful.

Unfortunately I can't relay better debug information. Usually the best thing to do is try a simplified version of what you want then build up from that.

I get a text picture that says there are only a few library functions I can use. I'd like more.

Yes, the only things available are a subset of the python math module that provides the most commonly used mathematical functions from the C library. If additional functions would be really useful, you could email me a request.

The picture is just like the last one I made, not what it should be.

Your C expression got past the interpreter in a way that I was not able to catch. This is unusual. More often you get the general error picture.

The picture is in colour but it's supposed to be greyscale.

You have used one of the strings "red", "green", "blue", somewhere.

Oh no I haven't.

Ah, you've used "rand()" and you'd like it to just produce a single random value at (x,y) not separate values for red, green and blue? It's a fair cop. That was an implementation decision I'm afraid.

The picture is supposed to be in colour, but not those colours.

When a colour is multiplied by a negative value, that colour is taken away! (Try setting the picture to -1*green, for example.) It's usually simplest to keep your colours positive.

The ternary operator isn't working right.

Try using multiplications by conditions rather than ternary operator. Also add brackets for extra parsing protection. But, I have to fess up, there is something a bit broken here. Annoyingly Python doesn't provide a plug-in replacement for C's (much superior) ternary operator. To do full, robust translation, you need to implement a mini-parser to rearrange keywords and associations to any depth of complexity. I haven't done that, so sometimes things go wrong. Sorry.

One-liners are just 256 x 256 pixels. Can't they be bigger?

They certainly can be bigger, but you wouldn't want to run the program on a webserver. Here's a 2048 x 2048 one-liner (click on the image to get the full-sized version). Higher resolutions better reveal how much detail you can get out of a one-liner. This coiled green tube, complete with all its shading and simulated specular reflections is generated from the single line:

green*sqrt(sqrt(2*(x*x+y*y) - 2*sqrt(x*x+y*y)*(x*cos(sqrt(x*x+y*y)/40.0)+y*sin(sqrt(x*x+y*y)/40.0))))-red*sqrt(sqrt(2*(x*x+y*y) - 2*sqrt(x*x+y*y)*(x*cos(sqrt(x*x+y*y)/30.0)+y*sin(sqrt(x*x+y*y)/30.0))))-blue*sqrt(sqrt(2*(x*x+y*y) - 2*sqrt(x*x+y*y)*(x*cos(sqrt(x*x+y*y)/50.0)+y*sin(sqrt(x*x+y*y)/50.0))))

Green spiral