A lot of what we use today is extended from our analog past: email, digital
books, and digital photos are more or less direct carryovers from physical
letters, books, and photos. And this tendency has bled into hardware products:
We’ve extended $0.05 pencils and $0.005 paper by creating $200 digital pencils
and $1,000 digital tablets. By carrying forward some of the elegance of pencil
and paper into the digital realm, we cheat ourselves out of discovering entirely
new approaches.