Unrealized congruences beauty in our everyday's life

we know the proverb
known is a drop and unknown is an ocean.
and change it slightly
which is best suited for mathematics
known applications are finite and unknown applications are infinite

Own point of view.
let us consider three varities of peoples.
first one be the ordinary peoples
ask the question
time right now is 2'o clock
(1)after 5hours what might be the time?
(2)after 17hours what might be the time?
for that they will say 7'o clock
what it means 5 and 17 both represent the same thing
time={1,2,3,4,5,6,7,8,9,10,11,12}
after every 12 hours or multiple of it it comes to the same stage where it was
originally.
This is not only happening on time everything in our daily life when it comes to date
we will consider 365,366 and 7 in case of days.like that so many examples
now the second variety programmers .
let us take the integer data type in c
int i=0;
for(; ;)
let us construct and infinite loop what will be happening it is going on
infinite loop .what is so special about this infinite loop .
0,1,2......,32767,-32768,-32767,.......0,1,2......
int ={-32768,-32767,.......0,1,2......32767}
Actually good programmers know about it.
But they didn't realize the innerbeauty of congruences .
But the third people who are the best people doing a great dedicated service
to society know the inner beauty hidden behind these.They are mathematicans who rules the world virtually.
The great disadvantage of mathematics is it's advanatge .
Because Behind everything maths is hidden .
Once you started exploring it you will realize the beauty.
After that what is the difference between you and other people
you observe they see
something make sense to the persons those who have knowledge about them