a simple knn demo experience with a clear interface
with JAVA
初始17个样本点，在面板上分别用红蓝橙三色区分。鼠标点击代表新加的点，自动归类并上色。
There are 17 sample points on the panel, divided by color(red, bule and orange). Adding new point by clicking, it will be classificated and colored automatically.