Simulation II – edge growth. A representative simulation of the edge growth pattern (see text). Cell cycle time, simulation length and cell color-coding conventions are as described in Figs. 10 and 11. Cell color-coding is by cell cycle phase. Note the enlarging central area of post-mitotic cells within each hemi-diaphragm (white), representing differentiation of central cells before peripheral cells. As in Simulation I (Fig. 11), the non-muscular central tendon is preserved, the left posterior PPF defect does not enlarge, and the classic hemi-diaphragm curvilinear morphology is not achieved.