diff-world tagline and header intro: `hook_world_alter();`

[naturallymitchell]

https://www.redbubble.com/people/buzkall/works/26970591-hook-world-alter?p=t-shirt

https://www.js.geek.nz/blog/hookworldalter-t-shirt-design

maybe it could be simplified to make it more broadly accessible, like world_alter()