Breakable object that can be fixed with glue
A raw egg
Break the breakable item (or show two broken pieces) and have a participant come up and glue them together. Discuss making mistakes and making restitution. Break the egg in the bowl and have another student come up and try to put the egg back together with glue. Discuss why it cannot be done.
Explain that some things can be forgiven but cannot be restored. (Taking someone's virtue, life, or sometimes, a person's good name.) Teach them the seriousness of those mistakes we cannot mend or restore. Encourage them to stay with and value the gospel principles and to keep the commandments and repent.
Luke 13: 3
Alma 12: 24
D&C 16: 6; 42:18; 76:32-35