Does anyone remember "flip flashcards" for new readers?

[lmintzer]

I don't know if that's really what they're called. . . I was wondering if anyone has seen these lately. When I was little, my parents taught me how to read using these flashcards: each one had a suffix, and then the first letter or letters could be flipped and changed. For ex., a "c" could be added to "at" and then flipped to a "b". There were 3 letter sets and 4 letter sets if I remember correctly.

I looked for these in a teaching store and didn't see anything like them.

Jack is showing reading readiness and these would be great for him.

Thanks!