now that we spend so much of our money through electronic means, it is often difficult to gauge our spending habits
without the physical reminder of cash. the proverbial wallets is a project by MIT’s media lab that aims to give digital
money a physical presence. the set of three digitally enhanced wallets don’t actually hold money but instead provide
feedback that let’s the user know their personal balances and transactions. one wallet resists opening based on how
much money the user spend in a month, while another features a vibrating mechanism when the bank processes
a transaction. the third swells up and down to reflect the remaining balance in the bank account. the project is the
work of MIT students john kestner, daniel leithinger, henry holtzman, emily tow and danny bankman.

http://eco.media.mit.edu/proverbialwallets