Well there are only three different size boxes available for the ancient age. The easiest way to explain it is to show you.
NOTE: I changed the size of the tech boxes by reducing the border quite a bit. I did this so that I could fit more techs in one Era. There are four column and 15 rows. It is sorted like this:
Researched Researching Available Unavailable
__________________________________________
...............|................|...........|............... Ancient Medium Sized Box
...............|................|...........|............... Ancient Medium Long Sized Box
...............|................|...........|............... Ancient Large Sized Box
__________________________________________
...............|................|...........|............... Middle Short Sized Box (Doesn't exist in the Ancient Section)
...............|................|...........|............... Middle Medium Sized Box
...............|................|...........|............... Middle Medium Long Sized Box
...............|................|...........|............... Middle Large Sized Box
__________________________________________
...............|................|...........|............... Indust Short Sized Box
...............|................|...........|............... Indust Medium Sized Box
etc... etc...
Notice how the top section does not have a small box. That is where the small box for the ancient era goes.
NOTE: I changed the size of the tech boxes by reducing the border quite a bit. I did this so that I could fit more techs in one Era. There are four column and 15 rows. It is sorted like this:
Researched Researching Available Unavailable
__________________________________________
...............|................|...........|............... Ancient Medium Sized Box
...............|................|...........|............... Ancient Medium Long Sized Box
...............|................|...........|............... Ancient Large Sized Box
__________________________________________
...............|................|...........|............... Middle Short Sized Box (Doesn't exist in the Ancient Section)
...............|................|...........|............... Middle Medium Sized Box
...............|................|...........|............... Middle Medium Long Sized Box
...............|................|...........|............... Middle Large Sized Box
__________________________________________
...............|................|...........|............... Indust Short Sized Box
...............|................|...........|............... Indust Medium Sized Box
etc... etc...
Notice how the top section does not have a small box. That is where the small box for the ancient era goes.