Science Homework- Due Friday!

Kiddos are to bring in or make a house for their rock by Friday.  It can be made out of anything- a tissue box, legos, whatever!  Just something to house their rock.  It MUST be smaller than a small paper place though!  They were told that if it's bigger than that, they will have to take it home and start again!  These rock pets are running around wildly!  They need houses!! :)