Работа с шахматной доской в Vb

Option Explicit
Private Sub Command1_Click()
    Dim a1 As Integer, b1 As Integer, a2 As Integer, b2 As Integer
    a1 = InputBox("Введите текущее положение слона A=1;B=2;C=3; D=4;E=5;F=6;G=7;H=8(X)")
    b1 = InputBox("Введите текущее положение слона (Y)")
    a2 = InputBox("Введите местоназначение слона A=1;B=2;C=3; D=4;E=5;F=6;G=7;H=8(X)")
    b2 = InputBox("Введите местоназначение слона (Y)")
    If CanMove(a1, b1, a2, b2) Then
    Print "Ход возможен"
    Else
    Print "Ход невозможен"
    End If
End Sub
Function CanMove(x1%, y1%, x2%, y2%) As Boolean
    CanMove = (Abs(y2 - y1) = Abs(x2 - x1))
    CanMove = (x1 = x2 Or y1 = y2)
End Function

Function CanMove(x1%, y1%, x2%, y2%) As Boolean
CanMove = ((Abs(y2 - y1) = Abs(x2 - x1) AND Abs(x2 - x1)=1)) OR ((x1 = x2 AND Abs(y2 - y1)=1) Or (y1 = y2 AND Abs(x2 - x1)=1)
End Function

Function CanMoveKing(x1%, y1%, x2%, y2%) As Boolean
    CanMoveKing = (Abs(y2 - y1) < 2 ) AND (Abs(x2 - x1) < 2)
End Function

Function CanMoveQueen(x1%, y1%, x2%, y2%) As Boolean
    CanMoveQueen = (Abs(y2 - y1) = Abs(x2 - x1)) or (y2 = y1) or (x2 = x1)
End Function

Module Module1
    Public Structure Scell
        Public Column As Short
        Public Row As Short
    End Structure
    Public Function Rook(ByVal scFrom As Scell, ByVal scTo As Scell) As Boolean
        If scFrom.Column = scTo.Column Or scFrom.Row = scTo.Row Then
            Return True
        Else
            Return False
        End If
    End Function