Light Ball

"Stars are just a legend... Even if you go up, the only thing you’ll reach is this floor’s roof. That blue sky is created by shinsu, and the twinkles at night is just a Light Ball"

- Khun Aguero Agnis to Twenty-Fifth Baam

Light Ball (볼 라이트, Bol Laiteu) is the device similar to a giant Lighthouse that lights up each floor similar to a sun at day, while in the night it will appear as a moon or stars.

About
Several Light Balls seem to be present on each floor, with one major light ball being responsible for the day-night cycle and the rest acting as stars at night and additional lighting at day.

Notes and Trivia

 * During the Marriage Tournament the Light Ball was used as timing for when the preliminary challenge was over.