Windows in the colonnade on the left give a glimpse of their tiny rooms; sticks hanging on the walls were used to beat miscreants on the soles of their feet, a mandatory punishment for all novices.
The sticks on the wall were about 3 inches thick.  
mnli hypothesis: The sticks on the wall were about 3 inches thick.   premise: Windows in the colonnade on the left give a glimpse of their tiny rooms; sticks hanging on the walls were used to beat miscreants on the soles of their feet, a mandatory punishment for all novices.