wall sockets
pickaxes
by hand
then rope or nothing
NASA needed a way to drill under the moon's surface. So they invented a cordless drill, and soon after many other cordless tools, that was lightweight, small, and battery-powered.
the polarity of the battery is reversed
Buttons.
bikes
benches
pickaxes
carriages
Brief case
We used letters.
horses or their feet.
A pen and paper!
they use to walk
Fingernails!!
Horses