There is an object, humorously called the Aperture Science Weighted Companion Cube, in the game Portal. But, people like to play with things, and we like to play with the things we like, and we like to play in the spaces in which we like to play (on the surface, that's a tautology, but that's not just what I mean, I mean, we like to play in them and play sometimes means not following the rules), so, when people like the Companion Cube, they play with it across the spaces they like to play in.
Thus the Cube is not just in Portal.
People have included the Cube in...
- Spore (by EA) [examples]
- LittleBigPlanet (by Sony/MM) [example at 1:10+]
- Second Life (by Linden Lab) [example]
- EverQuest II (by Sony) [example]
One of these things is not like the other, however (and I won't claim that that is an exhaustive list).
Which one?
EverQuest II. In the first three, the majority of content is created by players/users; in fact, the point of those worlds is to have a lot of content created by players/users. (I include "users" since Second Life is not exactly a game.) In EQII the majority of physical (virtual) content is made by the game designers/maintainers at Sony. Mundane items, game actions, and conversation are content that are made by players, but a lot of important items are not made by players. Yet, in EQII there is the Cube (and many other cultural references).
We love to play with the things we love, and we will do so across the various spaces where we can play, even if that object is not from the space we are in. Thus, the Aperture Science Weighted Companion Cube is in a lot of places. Culture is not just objects and practices we create, culture is something that we further play with and redefine over time. I think "culture play" might be a good phrase for this fundamental human behavior, despite the title to this post where I use the phrase "cultural play", which is a better headline.
The four spaces in the list also include many other cultural references through cultural items and homage, because this is something that we, as humans, are driven to do.