Continuing your walk along the road, the trekker may find beautiful formations of rocks on the side of the street. Checkpoint number 7 lets you play with the surface of the rocks, its sound and the tactile sensation that the friction produces. The trekker is asked to rub a stone against the rock. If she/he does it for a long time, her/his body will undergo such an experience that the memory in her/his arm muscles will provoke a persisting tactile sensation even after the action has ended.
The checkpoint is shown on this map: