What the…?

Janka (workmate) just discovered a German book called “Programmieren spielend gelernt mit dem Java-Hamster-Modell” in the office. It’s a tutorial book for learning the Java programming language. At chapter 14.1 it says: “Up to now the hamster is able to remember things only a very limited way. He just can use grain or boolean variables.” What the heck? “Grain or boolean variables”? I would feel like someone takes the mickey out of me while using this book. But hey: At least the book was useful to give my workmates and me some funny moments during the lunch break. :-D