Moreover Plutarch (Plut. De Comm. 39) stated that Democritus had raised the following question: if a plane parallel to the base cuts a cone, are the surfaces of the section and of the base od the cone equal or unequal? If they are equal, the cone becomes a cylinder, while if they are unequal, the cone becomes an "irregular cone" with indentations or steps. This question could be easily solved through calculus and it's been suggested, therefore, that Democritus may be considered a forerunner of infinitesimals and of integral calculus.