It's not the same side of the physical world. The earth needs to be lit from the same side side as in starts in the diagram.
It is the same side, but not at the exactly same spot.
Explain yourself difference between Calendar year and Tropical year.
After full Solar day Sun is crossing Meridian.
After full Tropical year Sun is crossing Parallel.
There is no gear in the vacuum of space to synchronize these two different motions.
EDIT: If you still insist on gear, take small one with four teeth: morning, noon, evening, midnight.
Now, big one would have
1441 1461 (NOT
1440 1460) teeth around.
So, each four teeth are for one day of small gear, and the last
1441st 1461st is those "6 missing hours".
Calendar year is 365 rotations of small gear (
1440 1460 teeth).
We wake up, go to work, go back home, go to sleep by rotations of small gear.
Tropical year is 365.25 rotations of small gear (full circle on
1441 1461 teeth).
We plow our land, and now also go to vacations, by seasons, not by days.
After one Calendar year "noon" will point 1 tooth less than full circle.
After one more Calendar year "noon" will point one more tooth earlier (2 teeth less than full circle).
In fourth year we have to count one more rotation (4 more teeth) to have our Calendar year point to the original first tooth of Tropical year.
That is just because we don't want July 1st to be in winter, we will not have warm sea in Belize then.
For example, Arabic calendar doesn't make those corrections. Their months circulate through the whole year and each month can be in any season.
https://en.wikipedia.org/wiki/Islamic_calendar