The demos here have been drawn in the course of a student's homework critique, but contain information that can be useful to all working through this material.
It is important to keep in mind that these demonstrations have been done over the course of years. Given that the specific aspects of the lesson have changed over time as the material has been rewritten to either clarify or further develop how certain principles are applied, the older the demonstrations get, the more likely they are to have elements that are no longer fully consistent with how the material is covered now.
Be sure to look at the demonstrations critically - if they're listed here, they are done so because they are still of value, in some area or another. That said, if they contradict principles stressed in a more recent demonstration, remember that the more recent demonstration will always supplant the older.
The demonstrations higher in the list are newer, those further down are older.