用VB写的mondebroot集，鼠标选中区域可放大显示-VB wrote mondebroot set, the mouse can enlarge selected regional show

用VB计算两圆外公切线，并绘制到窗口。一个简单的实例，可用在绘制轧机钢卷的直径变化。-VB calculations with two circles tangent grandfather, and draw to the window. A simple example, can be used in drawing mill coil diameter changes.