Lennie killed a mouse and kept it in his pocket and then george tells lennie to give it to him. Lennie can't take care of things he kills everything he touches. The theme of this scene is lennie doesn't know his own strength.
Curly was fighting lennie but george told lennie to do something so lennie grabbed curlys hand and breaks every bone in curlys hand.Once again lennie can't control his strength and only stops when george tells him to. The theme is relationships between men and social differences.
Lennie accidently killed his dog and he gets upset. Lennies strength has accidently caused another tragedy. Lennie has physical strength but his weakness is he has no control over it.
George told lennie to imagine the ranch and whe lennie imagined it george shot him and killed him. George kills lennie out of mercy even though he was innocent. The theme is friendship because George kills Lennie out of love.