You enter your friend's room. He is not in his room. Although you see that on the bed there are two dogs, five cats, two giraffes and three pigs. Also, a couple of chickens and ducks are flying in the room.
Calculate the number of legs standing on the floor.
A red house is made out of red bricks. A yellow house is made out of yellow bricks. And, a blue house is made out of blue bricks. So, what is a greenhouse made of?
How can you throw a ball as hard as you can and have it come back to you even if it doesn't hit anything there is nothing attached to it and no one else catches or throws it.