pdl> p $indicies = $b->indexND($pos + $xfrm, 'truncate')->which($b % 2);
# Returns: empty
#
# Expected: Should contain two single element piddles:
# [17 25]
# OR, the indicies in the original matrix would be fine:
# [
#  [3 1]   # 17
#  [3 3]   # 25
# ]
# N.b. [2 2] would be omitted (value = 20, even), as would [4 2] (index out of bounds)