Superellipse

const (
    a = 200,
    b = 200,
    n = 2.5,
)
 
# y in terms of x
func y(x) { b * (1 - abs(x/a)**n -> root(n)) -> int }
 
func pline(q) {
    <<-"EOT";
    <polyline points="#{q.join(' ')}"
    style="fill:none; stroke:black; stroke-width:3" transform="translate(#{a}, #{b})" />
    EOT
}
 
# Generate an SVG image
say <<-"EOT"
    <?xml version="1.0" standalone="no"?>
    <!DOCTYPE svg PUBLIC "-//W3C//DTD SVG 1.1//EN" "https://www.w3.org/Graphics/SVG/1.1/DTD/svg11.dtd">
    <svg height="#{b*2}" width="#{a*2}" version="1.1" xmlns="https://www.w3.org/2000/svg">
    EOT
 
# find point pairs for one quadrant
var q = { |x| (x, y(x)) }.map(0..200 `by` 2)
 
[
    pline(q),
    pline(q »*« [ 1,-1]), # flip and mirror
    pline(q »*« [-1,-1]), # for the other
    pline(q »*« [-1, 1]), # three quadrants
].each { .print }
 
say '</svg>'