This is a small Java application that makes use of the OpenCV library to track a Pictionary Air pen.
You will need a copy of OpenCV for Java to run this application ... see https://opencv-java-tutorials.readthedocs.io/en/latest/01-installing-opencv-for-java.html
You can run the application from the project root directory with a command similar to ...
java -cp bin;C:/Users/dadecoza/opencv/build/java/opencv-455.jar -Djava.library.path=C:/Users/dadecoza/opencv/build/java/x86 PicAir