Cytokinesis is inherently a mechanical process, driven by active expansive and contractile stresses and Laplace pressure differentials (cortical tension x local curvature), all of which act upon the cell’s viscoelastic material. By developing a complete mechanical description of the cell, we could account quantitatively for cytokinesis shape change, including the kinetics of furrow ingression. Thus, cells divide by mechanics, not biochemistry. The relevant question then becomes how does the cell use biochemistry to generate these mechanics. The major papers describing this work include Zhang and Robinson, PNAS 2005; Reichl et al. Curr. Biol. 2008, and Poirier et al. PLoS Comp. Biol. 2012.