Thought it might be useful having my chunk documented somewhere on my blog so that I can keep in mind what I am going to be doing:

CHUNK 61
TITLE Classes 2
DESCRIPTION This part of the book should introduce the code behind a class; this will require teaching of the highest order. This is a repeat of the previous chunk. Classes are so dificult to understand so we have decided to repeat the teaching
OUTCOME
Be able to understand the code of a simple class programmed in no more than 30 lines of code
REFERENCE Greenberg 304
HINT Try and describe a class that implements some simple graphics. Do enough teaching on constructors to get you throuugh but do not go to town on this: there will be more teaching on constructors later. Make the arguments lists a little more complicated than the previous chunk of the book, say three arguments maximum.
PROGRAM Difficult task: try and develop a class that is a little more complicated than the one that you describe and make it do something really visual.