The cell theory developed in the early 19th century teaches us that only cells beget cells (1). As a consequence, the evolution of life on Earth is but a long sequence of cell divisions; wherever this sequence is broken, life ends. Cell division is not only how organisms perpetuate themselves, it is also one way in which complexity is built during development. The contribution of cell division to development is particularly striking in plants because plant cells are surrounded by stiff walls, making them clearly distinguishable from each other and fixing their spatial relation by preventing cell migration (…)