To build:
$ git clone https://github.com/dfridovi/sketchpad
$ javac Sketch.java
To run:
$ java Sketch
sketchpad is almost completely mouse-operated. To begin, click on the "Point" or the "Line" button, near the top of the window. A point requires one click on the drawing pad, and a line requires two. To enter constraints, click the desired button, and then click the two shapes (note that they will be highlighted after each click, and unhighlighted after the system enters the new constraint). To create a composite shape, you must first group some primitive shapes together (by clicking on the "group" button, and then on each desired primitive, and then hitting "return"). Then, click on the "composite" button, and again on the desired composite from the drop-down menu.