for (y=1; y<=Bottom; y++) {
  c1 = [1,y];
  c2 = [2,y];
  c3 = [3,y];
  c4 = [4,y];
  c5 = [5,y];

  [1,y] = c5;
  [2,y] = c3;
  [3,y] = c1;
  [4,y] = c2;
  [5,y] = c4;
}