Reference for Processing version 1.2. If you have a previous version, use the reference included with your software. If you see any errors or have suggestions, please let us know. If you prefer a more technical reference, visit the Processing Javadoc.

rect(30, 20, 50, 50);
boolean b = false;
if(b == false) {
  line(20, 10, 90, 80);  // This line draws
} else {
  line(20, 80, 90, 10); 
}