Othello

float n = 0.125;
int count = 0;
int r = 55;
float[][] pos = {{218.75, 281.25, 218.75, 281.75},{218.75, 218.75, 281.75, 281.25}};
void setup() {
  size(500,500);
  background(0, 255, 0);
  strokeWeight(3);
  while (count<=6) {
    line(width*n, 0, width*n, height);
    line(0, height*n, width, height*n);
    n = n + 0.125;
    count++;
  }
  Circle();
}

void Circle() {
  int i = 0;
  while(i<4) {
    if(i%3==0){
      fill(0);
    }else{
     fill(255);
    }
    ellipse(pos[0][i], pos[1][i], r, r);
    i++;
  }
}