A block that covers nicknames

Imagine a block that prevents players' nicknames from being visible through it. Fans of secret bases would lay it along the room, like apartment soundproofing. This block works in both directions, which makes leaving the base not the safest process. Therefore, I also propose a variation of this block with more complicated crafting. With this variation, nicknames will only be visible on one side and remain invisible on the other, like Gesell's mirror.