Eugenia Chiappe, principal investigator of the Sensorimotor Integration Research Group at the Champalimaud Centre for the Unknown, Lisbon, Portugal is standing in her office. There is a door, maybe three meters away, and the floor is flat and clear. Eugenia, who intends to walk in a straight line to the door, takes a second to measure the distance and the terrain. She closes her eyes, walks four steps forward, and bumps into a chair to her right.