i object combname
This command is used to make an instance of an object. An instance of an object is produced by creating a combination and making the object a member. In this case, an instance of "object" is made by creating the combination record "combname" (if "combname" does not already exist) and adding "object" as a member. If "combname" already exists, then "object" is added as the next member.
An instance is used to refer to an object, without making actual copies of the object. Instances are useful when one is adding a certain component to a target description many times. Furthermore, any modifications to an object which has been instanced need only be done in the original (prototype) object. These modifications will then be automatically reflected in all the instances of the object.
Examples:
i heround he1 .he1.
i heround he2 .he2.
i heat heat1 .heat1.
i heat heat2 .heat2.