Shambolica

Hi, I'm working (playing) in VB.net and want to create a yin-yang symbol, using a few circles and a sine wave. Everything is OK except I can not find an easy way of filling in the black and white areas of the symbol. I did this program a while ago in previous versions of VB and just copied in an API reference that I found in a computer magazine article (PCW). Am I right in concluding that .net does not have a built in function for flood filling? If this is the case, isn't that kind of sad? :( Bit of an obvious oversight. I'd appreciate other's opinions. In the meantime, I'll try and find an example (probably right here) of that external floodfill in action. Thanks