How do you know that the block you are drawing was not already made by someone else 48 years ago?

you don't.

You don't know. But it doesn't matter. If you design a block you like, use it.

Do I get to name it?

of course

I would think, you could copyright it and name it. It's your original design. If someone finds the same design was copyrighted before yours or is an open market design, you'd have to rescind your copyright.

Oh, I don't plan to copyright. It's not as though I were planning to sell them. Just needed to know if I would be hurting someone else.

There was a big to-do some years ago about the card trick block. A quilt designer said it was an original design and not in the public domain. I don't know whatever happen about it but I guess nothing.