The creator of the Triangle of Power (<a href="https://www.youtube.com/watch?v=sULa9Lc4pck" rel="nofollow">https://www.youtube.com/watch?v=sULa9Lc4pck</a>) and the Essence of Linear Algebra (<a href="https://www.youtube.com/watch?v=kjBOesZCoqc" rel="nofollow">https://www.youtube.com/watch?v=kjBOesZCoqc</a>). He is now trying to focus full time on online math education.