I believe the first consumer optical mouse would beg to differ.
An old Thermos that is of the glass-lined vacuum filled sort is dangerous, due to the potential of breakage.
Ah, brief. Much C was written in that jewel. It is the reason many of my text editors have been configured with blue as a background and white foreground.
EARTH smog | bricks AIR -- mud -- FIRE soda water | tequila WATER