Testing with his commissioner friend

But yes! I could test it with my friend Klaus! thought Walter.

Klaus Knackler was a detective with the police in Walter's city. Walter had often helped him with his inventions in the past.

Knackler had a daughter named Gabriella who, with her friends Tom, Karsten and Kurt, kept solving criminal cases!

Finally, shortly afterwards, the doorbell rang on Walter's door. "Walter?"
"Come in, I'm in the basement!" answered this.

Klaus quickly went to the cellar. And was amazed, because there ...