Corner is a routine which allows you to perform a torn and restored card effect.
The spectator selects a card and signs the corner. Then the corner is torn and kept safe in spectator's hand. Then another spectator signs the face of a blank card, and the magician tears the blank corner.
And now imagine, the magician restores the two pieces in one card. Impossible, unbelievable. Give this impossible souvenir to your spectator.
Easy to construct gimmick
Very powerful effect with a strong impact
Everything is fully examinable
No special ink, no special glue
Perfect for street magic