int numStrings = 50;
size(400, 200);
background(255);

float gapX = 1.0 * width / numStrings;
float gapY = 1.0 * height / numStrings;

for (int k = 0; k < numStrings; k++) {
  stroke(255, 0, 0);
  line(0, k*gapY, k*gapX, height);
  stroke(0, 0, 255);
  line(k*gapX, 0, width, k*gapY);
}

save("lineArt3.jpg");