river

private List<Vector3Int> GetRiverPath(Vector3Int start, Vector3Int end, System.Random random)
{
    List<Vector3Int> path = new();
    Vector3Int current = start;
    path.Add(current);

    while (current != end)
    {
        Vector3Int remainingDistance = end - current;
        int k = Sign(remainingDistance.x);
        int l = Sign(remainingDistance.y);
        Vector3Int direction;
        if (k != 0 && l != 0)
        {
            Vector3Int[] directions = new Vector3Int[3] { new Vector3Int(k, 0),
                new Vector3Int(k, l), new Vector3Int(0, l) };
            direction = directions[random.Next(directions.Length)];
        }
        else
        {
            Vector3Int[] directions = new Vector3Int[3] { new Vector3Int(k + l, k + l),
                new Vector3Int (k, l), new Vector3Int(k - l, l - k)};

            foreach (var dir in directions)
            {
                if (path.Contains(current + dir))
                {
                    path.Remove(dir);
                }
            }

            direction = directions[random.Next(directions.Length)];
        }

        current += direction;
        path.Add(current);
    }

    return path;
}