When I wasn't looking, Shane (aka Mr. Hammer) showed his sister (Audrey, aka Mrs. Paint) an idea he had seen on Pinterest from blogger FthatS (now blogging as A Green(ish) Life). He liked it, she liked it, so he went shopping for supplies.
When he started, I thought Shane was building a massive display unit.
But he wasn't. He was building a whole bunch of box shelves that can be used individually, in small groups, or as a unit (but with many shape options). I love this set.