The array type does not seem to have a way to insert another array inside one array. One can do: irb(main):001:0> a = [ -1, -2, -3, -4, -5, -6, -7, -8, -9, -10, -11] [-1, -2, -3, -4, -5, -6, -7, -8, -9, -10, -11] irb(main):002:0> a[10] = [3,4,5] [3, 4, 5] irb(main):003:0> a [-1, -2, -3, -4, -5, -6, -7, -8, -9, -10, [3, 4, 5]] irb(main):004:0> a.flatten! [-1, -2, -3, -4, -5, -6, -7, -8, -9, -10, 3, 4, 5] which is fine, but: irb(main):012:0> a = [[1, 2, 3], 8, 9, [0, 1, 2]] [[1, 2, 3], 8, 9, [0, 1, 2]] irb(main):013:0> a[2]=[11,12,13] [11, 12, 13] irb(main):014:0> a [[1, 2, 3], 8, [11, 12, 13], [0, 1, 2]] irb(main):015:0> a.flatten! [1, 2, 3, 8, 11, 12, 13, 0, 1, 2] is not what I want, because it has flattened the whole array. Is this a case for an "insert" method for Array? Or "Is There A Better Way To Do It?" Hugh hgs / dmu.ac.uk