public static IEnumerable<NodeElement> Neighbors(NodeElement id, Seeker seeker)
    {
        Direction curDir;
        if (seeker._start == id)
        {
            //if this is the first node, get the general direction from it to the goal of the path
            curDir = new Direction(Mathf.Clamp(seeker.LastDestination.x - id.x, -1, 1), Mathf.Clamp(seeker.LastDestination.y - id.y, -1, 1));
        }
        else
        {
            //otherwise, get the direction from the seeker's last node to this node
            curDir = new Direction(Mathf.Clamp(-seeker.camefrom[id].x + id.x, -1, 1), Mathf.Clamp(-seeker.camefrom[id].y + id.y, -1, 1));
        }
        //if the direction is horizontal, add forward, and if the sides are unpassable, add their forward nodes too
        //if the direction is vertical, do the same but with y and x reversed
        //if the direction is diagonal, add the forward, left, right node
        if (Mathf.Abs(curDir.x) == 1 && curDir.y == 0)
        {
            //horizontal
            NodeElement middleForward = GetNodeAt(id.x + curDir.x, id.y);
            NodeElement right = GetNodeAt(id.x, id.y + 1);
            NodeElement left = GetNodeAt(id.x, id.y - 1);
            if (middleForward != null)
            {
                if (middleForward.Passable())
                {
                    yield return middleForward;
                }
            }
            if (!right.Passable())
            {
                NodeElement rightForward = GetNodeAt(id.x + curDir.x, id.y + 1);
                if (rightForward != null)
                {
                    if (rightForward.Passable())
                    {
                        yield return rightForward;
                    }
                }
            }
            if (!left.Passable())
            {
                NodeElement leftForward = GetNodeAt(id.x + curDir.x, id.y - 1);
                if (leftForward != null)
                {
                    if (leftForward.Passable())
                    {
                        yield return leftForward;
                    }
                }
            }

        }
        else
            if (Mathf.Abs(curDir.y) == 1 && curDir.x == 0)
            {
                //vertical
                NodeElement middleForward = GetNodeAt(id.x, id.y + curDir.y);
                NodeElement right = GetNodeAt(id.x + 1, id.y);
                NodeElement left = GetNodeAt(id.x - 1, id.y);
                if (middleForward != null)
                {
                    if (middleForward.Passable())
                    {
                        yield return middleForward;
                    }
                } if (right != null)
                    if (!right.Passable())
                    {
                        NodeElement rightForward = GetNodeAt(id.x + 1, id.y + curDir.y);
                        if (rightForward != null)
                        {
                            if (rightForward.Passable())
                            {
                                yield return rightForward;
                            }
                        }
                    }
                if (left != null)
                    if (!left.Passable())
                    {
                        NodeElement leftForward = GetNodeAt(id.x - 1, id.y + curDir.y);
                        if (leftForward != null)
                        {
                            if (leftForward.Passable())
                            {
                                yield return leftForward;
                            }
                        }
                    }

            }
            else
                if (Mathf.Abs(curDir.x) == Mathf.Abs(curDir.y))
                {
                    //diagonal
                    NodeElement middleForward = GetNodeAt(id.x + curDir.x, id.y + curDir.y);
                    if (middleForward != null)
                    {
                        NodeElement right = GetNodeAt(middleForward.x - curDir.x, middleForward.y);
                        NodeElement left = GetNodeAt(middleForward.x, middleForward.y - curDir.y);
                        if (middleForward.Passable())
                        {
                            yield return middleForward;
                        }
                        if (right != null)
                        {
                            if (right.Passable())
                            {
                                yield return right;
                            }
                        }
                        if (left != null)
                        {
                            if (left.Passable())
                            {
                                yield return left;
                            }

                        }
                    }

                }

    }