With 3D printers growing to the size where they can build houses from concrete (right now), I can see our spacefaring offspring in a few hundred years flying to remote planets and 3D printing pyramids.

Are they going to decorate the innards of said pyramids with diagrams of themselves hauling stuff with sledges, water and ropes too?

"Ha! This will confuse the cr*p out of the buggers who try to figure how we did it."