Preferably, use a perforating wheel to cut,
but in lack of such, you can cut along lines with a scalpel,
taking care to not cut all the way to the edge.
Ah...Italian invention! However, we were introduced to this grater by friends in Berlin. Brilliant. Great for those nights when you have to cook something but don't have the gumption to reach for the metal grater. Too much effort! We store our Parmesan inside this contraption in the fridge, so it is always on standby. Our student lives would have been saved with this one. It's never too late!