View source for Cantor ternary function/Fig1

<center><asy>
size(100,100);

// recursive procedure, draws the fractal within the rectangle [x0,x1]×[y0,y1]
void f(real x0, real x1, real y0, real y1, int n) {
  if (n!=0) {
    real dx = (x1-x0)/3;
    real dy = (y1-y0)/2;
    draw( (x0+dx,y0+dy)--(x0+2*dx,y0+dy), defaultpen+1 );
    f(x0,x0+dx,y0,y0+dy,n-1);
    f(x0+2*dx,x1,y0+dy,y1,n-1);
  }
}

f(0,1,0,1,9);
draw( (0,0)--(1,0), arrow=Arrow );
draw( (0,0)--(0,1), arrow=Arrow );
</asy></center>