What Am i 'buildin? (1-4 players)

What am I building:A house? A normal block? With the tools I left you, you could build anything.I was wondering to make a new survival map, when I though: Why continue with survival right now since I have 3 of the maps up?
So I thought of making this cool little minigame:Rules:(Must have 1-4 players) Somone builds Something in the middle of the arena, the other players have to guess it.If in 5 minutes they dont guess it the builder has to say what it is.

Once the builder has been guessed or had told the word, re-download the map if you want to do round 2, 3, (So on)