"Freitag" aber nicht Freitag

Today students have a "free day" to explore Berlin cultural sites and areas of their own choosing (and today is Thursday (Donnerstag) not Friday (Freitag)). We are meeting up at 6pm for a unique and highly anticipated culinary experience. Suffice it to say, the visual images you'd get from inside of the "dunkelrestaurant" are literally identical for all present. How is this possible? Answer: we ate in complete darkness and were served by visually-impaired and blind peoples.