Maneki Neko comes in many different colors but the most popular one is the tri-color.

The theoretical questions and conceptual issues. According to legend, very rare events (XXY tricolors tomcats or four leaf clover) bring good luck to their finders, an association between rarity and luck (as a shared trait).

Risk calculation is not restricted to a small set of classical exercices since problems of actual life are much complex and interesting than "calculation of being a Duchenne carrier given one affected, one non affected child".