 Complete the following phrase:  The driving force behind the founding of the Ring were Hugo Häring and Ludwig Mies van der Rohe who shared an office in Berlin at the time. Both were already members of the Zehner-Ring Ring of Ten, that was founded two years before with similar aims. Because its work didnt produce any results worth mentioning  as the Luckhardt brothers put it  they decided to extend the group in terms of geography and membership. In a letter dated April 1926, they asked several architects in Germany and Austria to join. Shortly after they were invited to a constitutional meeting in Berlin. The members of the Novembergruppe November-Group, which had been founded in 1918 and whose members, a collective of painters, sculptors and architects, were seeking to transpose the impulse of the 