Clem was resting on a log the day the nanobot came. It arrived in a spaceship the size of a tiny carrot. The nanobot quickly rearranged the atoms of its ship into another nanobot.
“Ain’t you the cutest little fellers!” enthused Clem, as 2 nanobots became 4.
The 4 then set about rearranging some of the atoms in Clem’s log. Soon 4 became 8; then 16.
Clem belly-laughed a treat. “You tiny guys sure are somethin’!” he drawled as 16 became 32. Then 64.
After a little while the nanobots started on the atoms of the tree beside Clem and 2048 became 4096. Amazed in a truly simple way, Clem watched the tree dissolve into nanobots. He was still being amazed as 1048576 nanobots inevitably surrounded him and turned him into 2097152 nanobots.
Three hours later, the rest of the Earth had been efficiently converted.
After a short rest, the substantial cloud of nanobots then morphed individually into little spaceships and headed back out again in search of even tastier worlds.