Pen on printer paper.
 
Georg Cantor gave birth to the higher infinities.  
 
Further reading:
 
https://genealogy.math.ndsu.nodak.edu/id.php?id=29561
 
https://www-history.mcs.st-andrews.ac.uk/Biographies/Cantor.html
 
https://en.wikipedia.org/wiki/Georg_Cantor
 
http://cantorsattic.info/Cantor%27s_Attic