design.txt

One of the core pieces of my design is the buttons objects, the objects that contains all the common pieces of 
processings code keyed by category. I thought about hard coding in the block menus, but I realized that it would
be difficult to change or update which pieces of code the teacher wanted in the menu. This way, it's easy to 
customize Training Wheels to a particular lesson or even a particular student. I accomplished this with several
nested for loops, moving to a new column every six blocks in the advanced panel. 

Changing the variables to numbers upon being placed in the editor was also a significant design decision. 
Some students might lose interest or become frustrated if they have to understand and replace variables 
the first time they want to run a piece of code, but I also wanted to conserve a kind of 'template' for the code
so the students would know what the variables represent. 

I split the advanced menu into a horizontally scrolling tabbed menu to most concisely fit all the buttons. I
used icons instead of category labels for space purposes and to limit the amount of text on the screen. 

I included an exercise (decorating a cake) for practice, as well as the solution code. The buttons have click
handlers that trigger events like showing more content on the page. 

I also use regular expressions to parse the html in the editor before I run the code on the canvas, and prepend
the code with a block to keep the canvas a constant size (otherwise it defaults to 100x100).