... Rectangle(ByVal X1 As Integer, ByVal Y1 As Integer, ByVal X2 AsInteger, ByVal Y2 As Integer) ' Draw a rectangle Line (X1, Y1)-(X2, Y1) Line -(X2, Y2) Line -(X1, Y2) Line -(X1, Y1) End ... values of Y1, Y2 if Y1 > Y2 If Y2 < Y1 Then Temp = Y1 Y1 = Y2 Y2 = Temp End If ' Plotting dots inside the rectangle at 50 pixels apart Chương Mười Hai - Dùng Đồ Họa (Phần ... ' Make sure that X1 is less than X2 ' Swap values of X1, X2 if X1 > X2 If X2 < X1 Then Temp = X1 X1 = X2 X2 = Temp End If ' Make sure that Y1 is less than Y2 '...