 In this time he designed villas on the island of Korčula and in Zagreb, several industrial buildings, the District Labour Insurance Building in Mostar (built in 1930, today an ambulatory care facility), this building has a convex half-ring-shaped entrance with a porch, and a dynamical balance of the low office building and the tall volume of the residential part and stairways.After that, he designed the District Labour Insurance Building in Skopje (1932), which was important for Yugoslav architecture because it introduced Le Corbusier's principles, including ribbon windows.In 1926, Drago Ibler became a professor at the Zagreb Academy of Fine Arts, where he taught architecture until 1941.