 The IG Farben Building consists of six wings , connected by a gently curved , central corridor . This arrangement provides all of the offices with sufficient natural light and ventilation . This design approach for large complexes offers an alternative to the " hollow rectangle " schemes of the time , with their typical inner courtyards . The prototype of this form is the General Motors Building in Detroit ( 1917 – 21 ) by Albert Kahn . The building presents a very large and weighty façade to the front , but this effect is reduced by the concave form . 
