I started doing a course on coursera.org and I noticed the lecturer was using a clear whiteboard in front of the camera which enabled him to draw on the whiteboard while facing the students. It was very good so I searched for glass whiteboard and discovered it’s called a “lightboard” which is a glass whiteboard with LED lights around the sides. It was invented by Michael Peshkin from Midwestern University. Here he is explaining how it works:
In this new era of online learning the lightboard is a godsend. If you’ve got the skills you can build one yourself for less than $100. I also found a UK supplier that sells them for £819 but they’ve sold out.