From Core77
![](http://www.core77.com/blog/images/jsasaki.jpg)
Reciprocal Distrust Reciprocal Distrust by John Sasaki is comprised of two counterfeit detectors placed back to back.
As is customary, cashiers will be able to scrutinize a customer's bills using the "seller's" detector. However, as distrust must be reciprocated, customers will be invited to verify the authenticity of the change they are given back, using the "buyer's" detector.