Rough Noise Sketch

float inc = 0.008;
int density = 4;
float znoise = 0.0;

void setup() {
 size(720, 480);
 noStroke();
}

void draw() {
 float xnoise = 0.0;
 float ynoise = 0.0;
 for (int y = 0; y < width; y += density) {
   for (int x = 0; x < height; x += density) {
     float n = noise(xnoise, ynoise, znoise) * 200;
     //noise(x, y, z);
     if (mouseX>360) {
       fill(n+mouseY); }
       else {
     fill(n); }
     rect(y, x, density, density);
     xnoise += inc;
   }
   xnoise = 0;
   ynoise += inc;
 }
   znoise +=inc;
 }