Slovenia had unique geography - homogenous, compact nation with no big cities, but a network of townships, which helped the spread. It never actually reached beyond Zenica and Tuzla in Bosnia, and beyond Pancevo and Novi Sad in Serbia. The drill sergeant assigned us to the same bunk-bed, since we both showed up with died hair and he probably thought we were fags. In early eighties the Slovenian influence was felt more strongly in Belgrade than in Zagreb, because at that time Belgrade had less moronic obstructive party leaders than Zagreb. Croatian Slavonia and Serbian Vojvodina are part of the Panonian valley that stretches through Hungary.
Valley is actually a bottom of the sea that dried along time ago.
Parts of the valley are therefore under the sea level. Valley is known for some of the most fertile lands in the world. The surroundings of Vinkovci in Slavonia pretty much remind you of Stephen King's cornfield. Under communists, small peasants were declared capitalists and mercilessly destroyed and forced into collectives that destroyed agriculture and incentive to farm land. People left villages and moved to cities to live in slums.