These are the sketch notes.
Digital ones were created on Samsung Galaxy 8, using Autodesk Sketch Express (and Autodesk Sketchbook) Exported using Airdroid, and did minor post-processing on OSX (preview app)
Later, I have drawn several using good old pen-and-paper (and were scanned)
I am grateful to Sacha Chua for the inspiration.
Thanks Sunni Brown for the Visual Notetaking 101 course.