# Check that the most appropriate lower bound is selected
[t1,t2]->{ S[i,j] -> [i,j] : exists (alpha, beta :
    0 <= i <= 1 &&
    t1 = j+128alpha &&
    0 <= j+2beta < 128 &&
    510 <= t2+2beta <= 514 &&
    0 <= 2beta - t2 <= 5
)}
[t1,t2] -> {: 125 <= t1 <= 127 and 254 <= t2 < 257}
{[i,j] -> unroll[x]}