Recently, I stumbled upon a book "Seven Sketches in Compositionality: An Invitation to Applied Category Theory" where the authors decided to design the difficul

Recently, I stumbled upon a book "Seven Sketches in Compositionality: An Invitation to Applied Category Theory" where the authors decided to design the difficulty of the chapters like this: https://i.ibb.co/349JLsf/difficulty.jpg https://i.ibb.co/349JLsf/difficulty.jpg (image from the book) I like this approach better, because most math books have some easy introductionary chapters and then it gets harder and harder, because the authors assume that they laid out the basics in the first chapters. The authors might be right technically, but it's very hard for the readers to go through a chapter that is 100% new material. In "Seven Sketches in Compositionality" they try to somewhat reset the difficulty for each chapter by starting again with introduction and motivation for each chapter separately. This makes it much easier for me to get into the material of each chapter and to read the whole book.