What is the name of an instrument in the temple?

What people in that temple do is unknown and common among people.

That is to say, although the Holy Grail has been drawn, it must be thrown into a straight and a reverse three times in a row, which shows that the drawing is accurate and is the instruction given to you by God. If you can't throw the Holy Grail into a straight and a straight for three times in a row, it means that the draw is not yours and can't guide you.