The expression comes from the popular and common chicken-raising, and therefore, chicks, in the homes of people. In order to ensure that chickens should eat and have them all together and controlled placed them on a flat and wide bowl of mud ( pot or dish ) not very high walls. The chick who escapes from there should be reinstated ( returned to the fold, ) or you ran the risk of lost or die of hunger.Of ahi que, in a protectionist effort, who " take the foot of the pot " It is that which is exceeded, that violates the rules, well by default or by ignorance.The fact is that many of those who dared to remove the foot of the pot were then the promoters of the great advances of mankind. We find them in all areas of history. An exercise stimulating, because it would remind inventors and their inventions in a linguistic exercise designed to expand common vocabulary and scientific vocabulary that students handle. For example, Descartes and the Cartesian axes, Plato and the platonic love, etc.