I created the images for Fedora, CentOS and OpenSuse. it thought me a lot about the dependencies, Linux image builds, etc... it was creating 'container'-images before this was a general thing.
Many stuff gets invented in raw form much before everyone receives it in a much more structured way.
Around 2007 when Linux namespaces started getting better support, I had made a small executable to use these system calls and to spin up a squashfs image 'just for compiling stuff for another system'. Much later, this whole method was replaced with 'docker run'.
