WHY ARE THERE TWO "FLUSH" BUTTONS ON THE TOILETS?

I can't think about something else, it's hauting me...

Usually when flush, the other button is pressed at the same time

And sometimes you can't even reach it, for example:
https://ibb.co/41Z4GD4

So... why?

author=Tw0Face
That's simple. Developers of toilets want to make sure you flush your output properly, therefore they need more water which comes with multiple buttons to flush.

They are probably smarter than me then

author=Illy
One for liquids

One for solids

It's the same flow of water regardless of the button and as I said you can't press just one button
It's one of the mysteries of the millennium

author=kentona
There are two reasons for this design.

Number 1....

...and Number 2

FINALLY I understand... thank you