My Mother's Containers

I may have spoken about my mother's habit of squirreling away various kinds of containers: cardboard boxes, plastic cake holders, glass containers, the list goes on. Anyway, last week she was sitting on the couch chatting with me and the conversation took an odd turn,
"You know those boxes that  come with the blank checks the bank sends you?"
"Mm, yeah."
"They're very flimsy. I mean, they are very flimsy even if you manage to get them assembled."
I had not really thought of this as a problem, having taken a seminar in box folding in school, although what I was remembering could have actually been an intelligence test on my three-dimensional spatial perception. I seem to remember such things. My counselor said that my tests indicated I should inhabit a two-dimensional universe. He had a furrowed brow as he related this to me.
"Well, yes. They are rather flimsy."
Pause. Pregnant pause. I am always after her to throw out boxes, so I felt she was setting the stage for something.
"Well, it's a good thing I saved some of those sturdy boxes from the old days. I use them, and they are much more stable!"
She had a distinct note of vindication in her voice.
I tried to remember exactly how far back the glory days of personal banking were; 20, 30, 40 years perhaps; but the mists of time clouded memory.