The lion chases the mouse. The lion is not rough. The lion is not young. The lion needs the mouse. The mouse chases the lion. The mouse does not eat the lion. The mouse is big. The mouse is nice. The mouse is round. The mouse needs the lion. If the mouse needs the lion then the lion eats the mouse. If something needs the lion and the lion needs the mouse then it does not chase the mouse. If something does not need the lion and the lion does not eat the mouse then the lion does not need the mouse.
The lion does not eat the lion.