draw a special shape in excel cell

Hello everyone!

I got a excel file,when I input letters or numbers in a special cell it shows to me kinds of interesting shapes:

For example: if I input '1' in the cell, it will show me a folder, input ' 8' will show me a mouse. '7' will show a keyboard, and if I input 'J ' will show a smile face...

May I ask what kind of formatting in this cell? I don't know how to find the formatting definition of the cell.

Thank you!