Recording of Lectures Explained

Rig a webcam on the end of a flexible neck stand (or desk lamp) to point down at your desk, and grab a pile of blank paper and sharpies to solve/draw as if drawing something for someone sitting next to you.

Use your office or some other room that has a whiteboard. Place your laptop in front of it and record your lecture on the whiteboard with your laptop’s camera. Write large and with contrasting colors to be visible. What you will see live will be in reverse (as in a mirror), but the final version will be correct.