var indices = [
  [-7, 1, 5, 2,-4, 3, 0],
  [2, 4, 6],
  [2, 9, 2],
  [1,-1, 1,-1, 1,-1, 1],
]

for x in indices {
    say ("%s => %s" % @|[x, eq_index(x)].map{.dump});
}