| j0 + ((i1 * 4 + j1) + 3) * 2 - 6 = i0, j0 ≤ 0, i1 * 4 + j1 ≤ ~3, i1 * 4 + j1 < 0, abs(j0) < 2, abs(j1) < 4, i1 ≤ 0, j1 ≤ 0, i0 < ~7, i0 < 0 ⊦ i1 = i0 / 8 |
j0 ≤ 0, i1 * 4 + j1 ≤ ~3, i1 * 4 + j1 < 0, abs(j0) < 2, abs(j1) < 4, i1 ≤ 0, j1 ≤ 0, j0 + ((i1 * 4 + j1) + 3) * 2 - 6 < ~7, j0 + ((i1 * 4 + j1) + 3) * 2 - 6 < 0 ⊦ i1 = (j0 + ((i1 * 4 + j1) + 3) * 2 - 6) / 8