One of the benefits of
being a digital packrat having a digital file cabinet is that every old file can be a starting point for something new.
In PreCalculus, I decided to do a short conic sections unit to fill the awkward two weeks between the end of the third quarter and the start of spring break. We've centered all of our conversations around the idea of a locus of points. I realized yesterday afternoon that the Algebra 2 activity I described here would be a great way to have some inquiry and experimentation on the day before break.
The online collaborative tools have improved considerably since 2012 when I first did this. I put much of the lesson into Google Docs and PearDeck which made sharing answers for the final reveal much easier. Here's what the students had for values that either "escaped" or were "trapped" in the Complex Plane:
I compared this to the pixelated Mandelbrot set I hacked together in Processing from Daniel Shiffman's code five years ago. Still works!