picture frames. Those frames were sized for 4x6 photos, but that was definitely the inspiration. I measured the flashcards and then starting doing some online research. I soon realized that memo-sized clipboards would be just the right size for these flashcards. At less than $3 each, I got right over to Office Max and bought 4. And then I went back for 4 more!
And here's my second draft!
Plus, given the era when the cards were made, the clipboards are a good style match.