Software Diagnostics Institute

Review: "I returned it immediately. It has about 20 pages of nonsense. Lego photos that present categories and objects without any explanation. Saying "A picture is worth a thousand words" doesn't work in this case."
Comment: There are explanations for every picture, including mathematical notation, in plain English. The idea is to build the picture yourself, which is much more comfortable with bricks, at least for me. "A picture is worth a thousand words" was never meant in this case as there are plenty of category theory diagrams elsewhere.

Review: "This is not what I expected. I expected a bit more text and more than 16 pages per book
Comment: Some books have more than 20 pages and in the total amount of more than 50 pages with diagrams for the 5-part bundle. There are more than 100 pictures for 7 parts."

Review: "It assumes knowledge that I don't have and uses very unfamiliar representations."
Comment: These series are intended as a supplement to traditional category theory textbooks. You may also need some abstract algebra background and familiarity with formal logical notation, including quantifiers. It now includes free Part 0 that explains all necessary mathematical notation: https://www.dumpanalysis.org/VCT/VisualCategoryTheoryPart0.pdf There are also corresponding CoParts that use standard category theory diagrams.

Review: "Didn't find pictures of the Legos adding clarity. Might have worked for me with more explanatory notes? I like the idea of trying to explain visually but I think computer aided diagrams rather than Legos would have been clearer."
Comment: Thank you. I have been thinking about adding traditional diagrams as a supplementary aid. The main idea is to use bricks to build diagrams where arrows and objects are freely moveable.

Review: "I am sorry, but all those books are just diagrams build of lego. This not only doesn't help or explain anything, but its actually less useful than original books and diagrams the legos are based on. Interesting idea, but not worth 20 USD per few photos of lego. At least not for me."
Comment: There are more than 50 photos for various category theory concepts with notes for 20 USD, not a few.

Review: "Bought the product on the basis of Leanpub good name. The product was essentially pictures of lego. Very disappointed."
Comment: I'm sorry, each part in the bundle has a sample of a typical book page, at least 5 pages for the bundle you bought. Yes, this is a collection of annotated Lego diagrams with corresponding definitions in a mathematical language, which can also be used as a reference.

Review: This first book in the series has 16 pages of results from Category theory illustrated using Lego. I marked down this text due to the lack of explanation for any of the results, say how these results relate to existing mathematical experience. The use of the Lego to illustrate the results was also confusing. The different coloured Lego was used to describe objects and the arrows with the point of view of the camera looking down onto the surface of bricks. The resulting distinction between arrows became confusing, made all the more apparent by the use of a multicolored object/arrow diagram on page 1. Overall this work does not fulfill on its promise and only obfuscates.
Comment: I think this series should be evaluated in the context of Part 0 that explains all necessary mathematical notation: https://www.dumpanalysis.org/VCT/VisualCategoryTheoryPart0.pdf Different colored objects and arrows have corresponding annotations to distinguish between them. The color is the distinction too. it is not just Lego bricks thrown in on a page.