iPhone? If so, the markup tools in the native camera app also works ok

Preview does the job fine. View > Show markup toolbar, and go nuts

This is the content we need

Good to know! Here's hoping publishers manage to do an ebook version eventually

@martinlorenz.bsky.social i'm very interested in your book! Do you by any chance provide an e-book/pdf version? It would certainly make sharing this knowledge much more accessible for people like me who live in places where shipping costs makes it unfeasable to get it

I got quite a nostalgic mood from this one, it looks a lot like the trains in my hometown