I like this garden I drove by on Bainbridge Island.  It has horizontal space, typical two dimensional boxes, but also adds in a vertical space, providing an opportunity for plants that might trail and spread to instead travel up and out (peas, tomatoes, pumpkins).  It also gives support and an area to tie down tall unstable plants (flowering perennials, floppy shrubs).  And with gates that could be shut, it keeps out unwanted animals (deer and dogs).  I think it’s a very useful and attractive design and hope that I can see it during the productive summer months.