User blog comment:Blappp/AoE II Tech Tree revamp/@comment-27274076-20170202051124/@comment-27198062-20170202113859

the tech tree icons are definitely visually appealing, but it would also be a lot of work to take a screenshot of every single building, technology and unit twice (once available, once unavailable, except for common ones).

About the structure: I don't really know how to do that, as far as i can tell now it's left to right and top to bottom, it's not too bad, but your sequence also seems solid.