Sometimes for machine learning experiments, I need a simple way to pick points in the plane as samples from different classes. Here's a GUI to do that. Pick points with the mouse. Then you can copy the text-based representations maintained below.
It's initially populated with an example from two classes sampled from Gaussians.
Ouput, L, is a list-of-lists of [x,y] pairs. L[i] is a list of [x,y] for class i.
Output is the pair [points,labels], where points[i] is one point [x,y] and labels[i] is the corresponding class
For binary problems, labels are +1,-1. For multiclass, labels are 0,1,2,...
Each line is: label x y