A*

  Private Structure Node

        Dim NodeX, NodeY As Integer 'the location of this node
        Dim ParentX, ParentY As Integer 'the location of this nodes parent
        Dim F, G, H As Integer

        Sub Clear()
            NodeX = 0
            NodeY = 0
            ParentX = 0
            ParentY = 0
            F = 0
            G = 0
            H = 0
        End Sub

        Sub GetScores(TargetX As Integer, TargetY As Integer)

            Dim dx, dy As Integer

            dx = NodeX - ParentX
            dy = NodeY - ParentY

            If dx = 1 And dy <> NodeY Then
                G = 14
            ElseIf dx = -1 And dy <> NodeY Then
                G = 14
            Else
                G = 10
            End If

            dx = Math.Abs(TargetX - NodeX)
            dy = Math.Abs(TargetY - NodeY)

            H = (dx + dy) * 10

            F = G + H

        End Sub


    End Structure

    Private OpenList(0 To 10) As Node
    Private ClosedList(0 To 50) As Node

    Public Sub Path(StartX As Integer, StartY As Integer, _
                    EndX As Integer, EndY As Integer)

        Dim CurrentX, CurrentY As Integer
        Dim TempNode As New Node

        CurrentX = StartX
        CurrentY = StartY

        With TempNode
            .NodeX = StartX
            .NodeY = StartY
            .ParentX = StartX
            .ParentY = StartY
            .GetScores(EndX, EndY)
        End With

        ClosedList(0) = TempNode


        Do While True

            If CurrentX = EndX And CurrentY = EndY Then

        'debugging : write the values of all nodes in ClosedList
                For intz = 0 To 50
                    If Not IsNothing(ClosedList(intz)) Then

                        Write((intz + 2) * 2, 2, ClosedList(intz).NodeX, ConsoleColor.Green)
                        Write((intz + 3) * 2, 2, ClosedList(intz).NodeY, ConsoleColor.Green)

                        Write((intz + 5) * 2, 2, ClosedList(intz).ParentX, ConsoleColor.Green)
                        Write((intz + 6) * 2, 2, ClosedList(intz).ParentY, ConsoleColor.Green)

                        Write((intz + 8) * 2, 2, ClosedList(intz).F, ConsoleColor.Green)

                    End If
                Next

            Else

                AddNeighbors(CurrentX, CurrentY, EndX, EndY)

                'find the last cell added to the closed list
                For intz = 0 To 50
                    If Not IsNothing(ClosedList(intz)) Then
                        CurrentX = ClosedList(intz).NodeX
                        CurrentY = ClosedList(intz).NodeY
                    End If
                Next

            End If

        Loop


    End Sub

    'this actually does all the work
    Public Sub AddNeighbors(X As Integer, y As Integer, TargetX As Integer, TargetY As Integer)

        Dim TempNode As New Node
        Dim LowNode As New Node


        For intx = -1 To 1
            For inty = -1 To 1

                If Not (X + intx) < 0 Then
                    If Not (y + inty) < 0 Then

                        'set stats
                        TempNode.NodeX = X + intx
                        TempNode.NodeY = y + inty
                        TempNode.ParentX = X
                        TempNode.ParentY = y

                        TempNode.GetScores(TargetX, TargetY)

                        'add to the next open spot
                        For intz = 0 To 10
                            If IsNothing(OpenList(intz)) Then
                                OpenList(intz) = TempNode
                                Console.Title = intz
                            End If
                        Next

                        LowNode.F = 9999
                        LowNode.G = 9999
                        LowNode.H = 9999

                        'find the lowest
                        For intz = 0 To UBound(OpenList)
                            If OpenList(intz).F < LowNode.F Then
                                LowNode = OpenList(intz)
                            End If
                        Next

                        'add to the closed list
                        For intz = 0 To UBound(ClosedList)
                            If IsNothing(ClosedList(intz)) Then
                                ClosedList(intz) = LowNode
                            End If
                        Next

                        For intz = 0 To UBound(OpenList)
                            If IsNothing(OpenList(intz)) Then
                                OpenList(intz).Clear()
                            End If
                        Next

                    End If
                End If

            Next
        Next


    End Sub