It is growing on just one brick. In a wall of white there is one hairy grey rectangle.
Today I pulled the brick out of the wall and took the mould for a walk. It looked so cute with its little red coller. People stopped me in the street to say "Oh! Isn't that a cute looking mould?"
I don't know what to do with it. I think I'll eventually throw it out unless it suddenly grows a huge mammery gland.