size (200,200);
background(255);
int x=0;//line
int s=1;//stroke weight
int c=255;//stroke(color)
while(x<200) {
      stroke(c,0,0);
      c=c-20;
      strokeWeight(s);
      s=s+1;
      line (0,x,200,x);
      x=x+13 ;
      }