> For the complete documentation index, see [llms.txt](https://trizen.gitbook.io/sidef-lang/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://trizen.gitbook.io/sidef-lang/programming_tasks/a/archimedean_spiral.md).

# Archimedean spiral

```ruby
require('Imager')
define π = Num.pi

var (w, h) = (400, 400)
var img = %O<Imager>.new(xsize => w, ysize => h)

for Θ in (0 .. 52*π -> by(0.025)) {
    img.setpixel(
        x => floor(cos(Θ / π)*Θ + w/2),
        y => floor(sin(Θ / π)*Θ + h/2),
        color => [255, 0, 0]
    )
}

img.write(file => 'Archimedean_spiral.png')
```

[Output image](https://github.com/trizen/rc/blob/master/img/archimedean-spiral-sidef.png)