Not futuristic: but adobe - the cheapest/oldest building material around - has this property naturally (on a 12hr cycle). Thick walls insulate from the heat dur

Not futuristic: but adobe - the cheapest/oldest building material around - has this property naturally (on a 12hr cycle). Thick walls insulate from the heat during the day, and radiate that heat during the night: It's hyper efficient. Building regulations killed it's use in America! Requiring the adding in of rebar actually makes it weaker... as well as more expensive than wood (go ahead and guess which groups lobbied for that set of regulations).