size(100, 100);
colorMode(RGB, 100);
color red = color(100, 0, 0);
color green = color(0, 100, 0);
color blue = color(0, 0, 100);
for (int y = 0; y < height; y++) {
  for (int x = 0; x < width; x++) {
    if (x < width/2 ) {
      stroke(red);
    } 
    else {
      stroke(green);
    }
    point(x, y);
  }
}