Small Gecko lizards have the amazing ability to climb and run on vertical surfaces even when they are completely smooth like glass. The adhesion ability of their foot doesn't function like glue or a sticky tape, usually our first thought when we see them running upwards a wall. If they used a glue-like physiology not only they would accumulate dirt and thus become incapacitated but they would also need a huge effort in order to unstick their foot in every step. The amazing mechanism that natural selection have provided the gecko is the subject of study in order to form similar functions artificially.