Source code in the sidef programming language

require('Imager')
define π = Num.pi

var (w, h) = (400, 400)
var img = %O.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')