Mark Lawrence said this quote

The holy stone looked for all the world like a small iron pineapple, its surface divided into squares by deep grooves, a tarnished silver-steel handle or lever held tight to the side. In ancient times the pineapple was ever the symbol of welcome, though the church used the objects in a different way. Apparently, each theological student of good family and destined for high office was given one on beginning their training and forbidden from pulling the lever on pain of excommunication. A test of obedience they called it. A test of curiosity I called it. Clearly the church wanted bishops who lacked the imagination for exploration and questioning.