Vladimir Propp analyzed Russian folk tales and identified 31 plot elements and 8 character types that commonly appeared. Propp found that while characters and stories varied greatly, the underlying narrative structures remained the same. These included character types like the hero, villain, and helper. Narrative theories also seek to understand common story structures, such as Todorov's three-step theory of equilibrium, disequilibrium, and new equilibrium, and the idea of binary opposition between two conflicting sides driving the narrative. Hansel and Gretel follows many of these common narrative patterns, such as having the children as heroes, the witch as villain, and a linear story structure moving from their initial situation to overcoming dangers in the forest.