Hindu temples are built as per the instructions given in the āgamas. The garbhagṛha or the sanctum sanctorum is the heart of the temple structure. The icon of the deity is placed in the centre of this. Below the icon, several objects are placed one above the other, starting with the ādhāraśilā (base stone). Over this are placed a pot, tortoise and lotus made of stone, two more tortoises and lotuses made of silver and gold and a funnel shaped tube called ‘yoganālā’ above which the slab brahmaśilā is placed. The brahmaśilā will be at the floor level. The icon is placed over this brahmaśilā.