teach from the board

why not slides?

• goes too fast, hard to follow
• previous slide disappears to show next one
• static, not interactive

chalk and blackboard

• https://people.math.harvard.edu/~knill/pedagogy/blackboards/index.html
• https://slate.com/human-interest/2014/10/a-history-of-the-blackboard-how-the-blackboard-became-an-effective-and-ubiquitous-teaching-tool.html
• crayola anti-dust chalk

markers and dry erase board