I suppose that Fred and Freda were goldfish and their goldfish bowl got broken, thus the glass. The stones could have been thrown through the letterbox so breaking the bowl but I don't know where the cloth fits in.
fred and freda are indeed goldfish,.a cat jumped up and grabbed the cloth on which their bowl was resting ,pulling the whole lot off the table with a crash and smash,the cat then runs out of the door with the cloth attached to 1 of his claws/paws.