Ian Johnson is the author of Tributary - an open source live-coding environment designed for prototyping data visualizations with D3. He also co-organizes the SF Bay Area d3 Meetup and makes educational D3 videos.
Bay Area D3 and Tributary
Ian field a few questions from the audience regarding the brush generator example. During the process of answering the questions, Ian demonstrates a color scale and address D3's AJAX convenience methods.