fullscreen float space = 33;
size(400,400);
smooth();
background(255);
for(float xPos = 50; xPos <= width-50; xPos = xPos + space){
for(float yPos = 50; yPos <= height-50; yPos = yPos + space){
if(random(100) > 30){
ellipse(xPos - 10, yPos, 10, 10);
}else{
ellipse(xPos, yPos - 10, 10, 10);
}
}
}