>>> T1:={[i,j]->[i,j,0]};
>>> T2:={[i,j]->[i,j,1]};
>>> R1:={[1:9,1:9]};
>>> R2:={[5,1:9]};
>>> codegen T1:R1,T2:R2;
for(t1 = 1; t1 <= 9; t1++) {
  if (t1 <= 4) {
    for(t2 = 1; t2 <= 9; t2++) {
      s1(t1,t2);
    }
  }
  if (t1 == 5) {
    for(t2 = 1; t2 <= 9; t2++) {
      s1(5,t2);
      s2(5,t2);
    }
  }
  if (t1 >= 6) {
    for(t2 = 1; t2 <= 9; t2++) {
      s1(t1,t2);
    }
  }
}

>>> codegen 2 T1:R1,T2:R2;
for(t1 = 1; t1 <= 4; t1++) {
  for(t2 = 1; t2 <= 9; t2++) {
    s1(t1,t2);
  }
}
for(t2 = 1; t2 <= 9; t2++) {
  s1(5,t2);
  s2(5,t2);
}
for(t1 = 6; t1 <= 9; t1++) {
  for(t2 = 1; t2 <= 9; t2++) {
    s1(t1,t2);
  }
}