Otherwise, the existence in the Buddha is symbolized by an vacant throne, as in the scene of Bimbisara together with his royal cortege issuing from the city of Rajagriha to visit the Buddha. Instead, aniconic symbols had been utilised. That is dealt with in additional detail in Buddhist art, Aniconic https://javatourbylocals.com/Blog/Discover-the-Rich-History-of-Borobudur-Temple-A-Journey-Through-Time/