Try to start generalizing the render() method so it could work for different configurations of displays

You don't need to solve the entire space of problems, but it is good to think about this:

Pay attention to where the number 16 show up and think about how you could make the code more general by replacing those with "configuration" variables (maybe specified in the constructor with default of 16?). Doing that as a first step doesn't change the behavior of your code, but it highlights some ways you might be able to generalize (or exposes how hard it might be). Either way it can do good things...