The question of how to rotate a PVector object (the data of the vector itself, I’m not talking about rotating while drawing) came up in my nature of code course yesterday. To do this, you’ll need to convert the vector to polar coordinates (radius + angle), adjust the angle, and the convert it back to cartesian to solve for the components (x and y). A function would look something like:

(Update thanks to Vilhelm’s comment below: You can also use a 2D rotation matrix!)

Now, this is really just a ruse. A big excuse for me to figure out how to get a Processing example in a wordpress post using processing.js! I was able to do this fairly quickly with three quick steps: