You have heard the story of the three pigs.  They are types only.  There were in fact many pigs.

They mostly lived in straw houses because some smart little pigs went back to first principles.  What are houses for? they wrote on a whiteboard in their brainstorming session.  They came up with a list.  Keep out the rain.  Privacy.  Store your stuff.  Straw houses were cheap and did all that just fine.

An even smarter group of pigs built houses of sticks.  Houses are supposed to keep out rain, they agreed, but not just for a season.  “We want a house that lasts until we die!” they said.

One pig was too poor to be smart.  Besides, he had a family, and it put into his mind thoughts of his own time as a child, of his parents and grandparents. He built his house of stone, since it had been the custom.  “Besides,” he said, “it may last for my children.”

Another pig built a rock house because it was beautiful.

And another pig built a rock house because he built it in similitude of the temple of God, whose dwelling was forever.

The wolf came.  The wolf always comes.  Only three rock houses remained.

Three rock houses, I said.  But I will tell you a mystery.  The three rock houses are really one.  The three pigs are really the same pig.