List<Vector2>[] appendLists(List<Vector2>[] l1, List<Vector2>[] l2)
{
List<Vector2>[] result = new List<Vector2>[2];
result [0] = l1 [0];result [1] = l1 [1];
for (int i=0; i<2; i++) {
for (int j=0; j<l2[i].Count; j++) {
result [i].Add (l2 [i] [j]);
}
}
return result;
}