time

many years ago the concept of time was quite different to the currently one.
seconds, minutes, hours, days, weeks, months, years, centuries, etc, had to be invented by the creative human mind.
Seconds, minutes used to be measured by the time it took to prepare rice.
Minutes, hours used to be measured by the time it took to get somewhere by foot or by horse.
Inventions spring up from necessities.
Time is one of the most important, useful, necessary, essential inventions that human being has created ever.