int i;

size(300,300);

for( i = 0; i < 300; i = i + 2) {
  //line(i,0,i,300);
  //point(i,i);
  
  fill(i,50+i,255-i);
  stroke(i,0,0);
  rect(i,i*i/1000,i,i);
  
  stroke(0,i,i);
  noFill();
  rect(300-i,300-i*i/1000,i,i);
  
  line(i,300-i,i*i,i);
  
}