settings.outformat = "pdf";
settings.render = 0;



unitsize(50mm);



real s(real x) {
  return min(x - floor(x),ceil(x) - x);
}

real Tpartial(real x,int n) {
  real result = 0;

  for (int i=0; i<n; ++i) {
    result += s((2**i)*x)/(2**i);
  }

  return result;
}

path Tpartial_path(int n) {
  path p;

  real x_step = .5**n;

  for (real x=0; x<=1; x=x+x_step) {
    p = p -- (x,Tpartial(x,n));
  }

  return p;
}



int n_max = 9;

for (int n=1; n<n_max; ++n) {

  draw(Tpartial_path(n),.2pt+(.9-.5*n/n_max)*white);

}

draw(Tpartial_path(14),.2pt+black);



shipout(bbox(2.5mm));