Someone wrote the Lord's Prayer on a grain of rice. They had to write very very small, of course. Someone wrote the letters "IBM" using gold atoms. That's writing about as small, physically, as you can.
Of course, mathematically, you can write very very small, can't you? Well, yes and no. You have to be precise about what you mean. So let's consider a simple problem with some simple rules.
Suppose we have a square sheet of paper. You are allowed to write on one side of the paper, only. You have a pen that can write letters of any size, and the pen writes a line that is very thin, that is, it's as thick as a "mathematical line".
How many times could you write the letter O using the given paper and pen? The individual letters may be of different sizes, but they must all be the same shape of a perfect circle and no letter may cross or touch another letter.
How many times could you write the letter X using the given paper and pen? The individual letters may be of different sizes, but they must all be the same shape, of a perfect X, and no letter may cross or touch another letter.
I give up, let me see the solution.