I like to work in A5 sketchbooks and notebooks, generally, and I tend to have at least one per project. That gets quite confusing at times, and I thought it would be nice to have a cover that holds a set of them at a time so I can carry all the ones I am working on at the same time.
This design is inspired by those lovely Midori Traveller books that have appeared on the scene recently - they are great, but not a useful format for me. Too narrow. So, anyway, here's how I made my own.