Can I Travel To Schengen Countries With German National Visa?

Can I Travel To Schengen Countries With German National Visa? According to the Schengen agreement you are allowed to visit all the states in the Schengen area, including Austria, Belgium, the Czech Republic, Denmark, Estonia, Finland, France, Greece, Hungary, Iceland, Italy, Latvia, Lithuania, Luxembourg, Malta, the Netherlands, Norway, Poland, Portugal, Slovakia, Slovenia, Spain … Can