Mengers Sponge in 2D

This is mengers sponge in 2D written in c using c sketch

website: https://anandology.com/

CODE

#include <stdio.h>
#include <sketch.h>
#include <unistd.h>

void sponge(double x, double y, double size, int depth)
{
    if (depth==0)
    {
        draw_rectangle(x,y,size,size);
    }
    else
    {
        double s = size/3;
    set_fill("black");
    sponge(x-s, y,s, depth-1);
    sponge(x+s, y,s, depth-1);
    sponge(x,y-s, s, depth-1);
    sponge(x,y+s, s, depth-1);
    sponge(x-s, y-s, s, depth-1);
    sponge(x-s, y+s, s, depth-1);
    sponge(x+s, y-s, s, depth-1);
    sponge(x+s, y+s, s, depth-1);
    }
    
}

int main (void)
{

    sponge(0,0,600,5);
    save_sketch("spo.svg");

}