This is a really cool pen holder by Thingiverser Roman Hegglin. Roman is very much an ideas man as this, and most of his latest things are slick computer generated images or STL files (the files that you feed to 3D printers). He has printed a lot of designs but seems to share first and share fast!
This Pi cup doesn't state the number of decimal places but if we estimate there are 40 digits per line and a quick count gave me 20 lines (I understand this is a spiral) it could be as many as 800 dp! So a handy aid memoir for your desk should ever you forget.
It certainly looks like a tricky print, but as someone with no experience in 3D printing that would be a guess. It's not impossible though as there are at least 10 made at the time of writing.
These two were made by Thingiversanaut crota on his Prusa i3, taking 13 hours and 7 hours for the large and small respectively.
Thanks very much to Roman for sharing this great Open Source design.