Generally speaking, in order to perform a full GC across the entire object memory, the virtual machine traverses (that verb again!) all reachable objects starting at some root, typically the global dictionary `viki.wiki`. As it visits all the reachable objects, it remembers which objects were visited. This allows the virtual machine to determine which objects were not seen during the traversal, and it is how the VM’s garbage collector determines what is garbage and what is not.
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