Kohaku has located the treasure left behind by Byakuya and the others, but it's encased in concrete. Senku has to devise a plan to quietly get at the contents inside, so as to not alert the guards.
Like the stuff that's in art classrooms?
مثل الذي في صف الفنون؟
Ma lo stesso gesso usato 
per le statue nei musei, quello?
Como aquilo que se usa nas aulas de arte?
Из него сделаны бюсты в классах изо?