This week the major organs of your twins begin to develop....their heart, which was divided into right and left chambers, beats 150 times per minute, twice as fast as yours....their skin is thin and clear and blood vessels are clearly defined....hands bend at the wrists....eyes begin to cover like eyelids and internal organs....perfect....it takes time and the ears become fuller Your appearance begins to change does, the size of the breasts and Your waist increases.... Eyelid: The eyelids are thin and transparent and almost cover the eyes.... Hand: The hands are bent at the wrist and facing the heart.... The fingers are still a little fuzzy and have become longer.... The brain: The nerve cells inside the brain have nerve pathways and are already branching out to form your joints.. The legs are growing.