[a3, b3, a2, b2, a1, b1] -> { s2[i] -> [i, 2] : i >= a3 and i <= b3; s0[i] -> [i, 0] : i >= a1 and i <= b1; s1[i] -> [i, 1] : i >= a2 and i <= b2 }
{  :  }
[a1, b1] -> { [i0, i1] -> separate[o0] : o0 >= 2 }