8 to 15 weeks. The fetus continues to move in distinct motor patterns, picking up new patterns such as localized movement of the arms and legs, hiccups, breathing-like movements, and stretches and yawns . The breathing-like movement of the fetus is necessary for stimulation of lung development, rather than for obtaining oxygen. At nine weeks, the fetus is able to bend fingers around an object; in response to a touch on the foot, the fetus will bend the legs or curl the toes to move away from the object. The face is well-formed and develops a more human appearance. Eyelids close and remain closed for several months. The different appearance of the genitals in males and females becomes pronounced. Toothlimbs are long and thin, and red blood cells are produced in the liver. A fine hair called lanugo develops on the head. The gastrointestinal tract, still forming, starts to collect sloughed skin and lanugo, as well as hepatic products, forming meconium (stool). Fetal skin is almost transparent. More muscle tissue and bones have developed, and the bones become harder. The first measurable signs of EEG activity occur in the 12th week. By the end of this stage, the fetus has reached about 15 cm (6 inches).