fullscreen
void setup() {
size(600, 600);
}
void draw() {
if(200< mouseX & mouseX<400){
background(mouseX-200,100,random(100));
}
else {
background(50,10,10);
}
for (int x=10; x < width; x = x + 40) {
for (int y=10; y<height; y=y+40) {
stroke(185,50,random(255));
strokeWeight(10);
fill(0, 200, random(255));
rect(x,y,20,20);
}
}
}