I think I like the looks of these better than Adirondack chairs. Looks like it might be possible to lengthen into a bench too, maybe.
https://www.instructables.com/id/Gerrit-Rietveld-Crate-Chair/?utm_source=newsletter&utm_medium=email
https://www.instructables.com/id/Gerrit-Rietveld-Crate-Chair/?utm_source=newsletter&utm_medium=email