Thank you @haejin for all the effort you put into producing these lessons. I fully understand why you prefer the videos over typing out your comments. However, that makes it very hard for me to follow because the video's are much lower quality.
Would it be possible to NOT type out the commentary, but include a still image of the charts AFTER you have made your marks? That would help those of us with vision problems be able to follow much easier. On the videos, often I cannot see any of your markings and all the numbers are blurred no matter how hard I try to clean them up.
Thank you for considering this and have a GREAT day!