There are lots of instances of certain classes of objects, for example brands (sticks). If you G BRAND, you will pick up all brands in the room. If you only wanted one particular brand, and not the others, it would be hard to reference it unless it had a unique name. Hence, you would eg. G BRAND4.

This looks odd at first, but is indispensible once you get used to it. For example, suppose you had earlier hurt RAT2 but it had fled. If you then entered a room containing six rats, you wouldn't want to KILL RAT because then you'd end up fighting all six! KILL RAT2, however, would select the particular rat you knew was low on stamina.