Secret cutlery code in the restaurant: How to tell the waiter that it wasn't tasty. The code was originally found in the work “On Dealing with People’ by Adolph Freiherr Knigge.
Even today it is common practice to give signals to the waiter using a knife and fork. The codes do not only apply in Germany and are interpreted differently depending on the country. In Italy, for example, it is unusual to place Cutlery crosswise.