रेखागवयन्यायः

This maxim originates from a story that one day, an illiterate rustic living in a village went to a forest, and enquired of an inhabitant of that forest about a Gayal which that rustic villager never saw before. The forester thereupon drew an outline on the ground to show the villager, what sort of animal a Gayal was. The foolish villager was satisfied. But on another occasion of his going into the forest when accidentally came across a Gayal he saw that the idea of the animal given him by the forester was quite wrong. It is used to denote that one should be careful in selecting his preceptor. An incompetent preceptor does more harm than good.