This peripheral blood smear demonstrates marked poikilocytosis (abnormally shaped RBC's) as well as some anisocytosis (variation in RBC size), though many are small (microcytes). This patient had beta-thalassemia, a hereditary disorder of beta globin chain synthesis that leads to ineffective erythropoiesis and a microcytic anemia. Some of the RBC's resemble jigsaw puzzle pieces.