Wilhelmwerk was an advertising studio ran by Wilhelm Heinrich Deffke and Carl Ernst Hinkefuss from 1916 to 1920 in Germany. Both designers were part of the modernist movement that was going on at the time in Germany, in fact Ernst was involved with the Bauhaus. Their work is a perfect example of the trends of that time, mainly the construction of illustrations based on simple shapes and bold colours. Their work field varied from book covers, propaganda, illustration books among others. It looks like they had a soft spot for animal illustrations, which are beautifully constructed and have a very contemporary look in a sort of abstract-pictographic way. You can check out more of their work at this website (in german). Lovely work pieces to take as inspiration for next projects.