Einstein's riddle or "Zebra puzzle" is a well known riddle attributed to Albert Einstein. In a neighborhood of five houses one is given some clues regarding the habits of the house owners and is asked to identify the one that owns the fish (or zebra in some variations).
It is said that only 2% of the population is able of finding the solution. I am not sure however, if this percentage refers to the people that are able to solve the puzzle without using a pen and a paper (or a computer). This is indeed very difficult and requires a beyond the average ability to hold too many pieces of information in one's mind at the same time.
This application provides an easier way to solve the puzzle. It presents the rules and the board in the same screen and allows you to easily make selections. It highlights red or green a rule automatically, when it is violated or fulfilled. It also offers easier variations of the puzzles, with fewer houses and properties.