What do you do with the four purple crystals in the Temple of Darkness in Zelda Phantom Hourglass?

In "The Legend of Zelda: Phantom Hourglass," the four purple crystals in the Temple of Darkness serve as a puzzle element. To progress, you need to activate all four crystals by striking them with your sWord. This will unlock the door to the boss room, allowing you to confront the boss and continue your adventure. Be mindful of the surrounding enemies while you solve this puzzle!