@lina Nobody's getting it (which is fine, cuz I didn't bother to explain the context), but it's poking at the fact that we use 'block' and 'mute' - which are verbs - as nouns, while 'friend' is already a noun. And that if you lexed 'block' as a noun, you'd be referring to a usually wooden cube-shaped plaything; and if you lexed 'mute' as a noun, you'd be referring to someone who cannot speak.
The idea was proposed to me by my little sister who is nonverbal.