Small and Smaller
According to the Treaty of Versailles, Germany was forbidden from developing and producing armament and military vehicles, including tanks. Engineers in that field left Germany and began working in other countries. This explains why German tank design skipped over the various cadavers that were built in other countries. German engineers worked on these dead end designs while foreign money paid for it. Nevertheless, this could not continue forever, and sooner or later, work had to start in Germany.
The first signs of a German tank building revival appeared in 1925. Naturally, all work was done in strictest secrecy. A year later, self propelled gun mounts on the chassis of commercial tractors began development. Development of the Armeewagen 20 also started around this time, a medium tank that evolved into the Grosstraktor on March 14th, 1928. The vehicle was conceptually new and had no foreign analogues, even though it somewhat resembled a shrunken down FCM 2C. The new tank would achieve a speed of 40 kph, which gave it high mobility on the battlefield.