It is most typical for these so-called ommatidia to have 6 sides and to be nestled together in a hexagonal tessellation, much like a tiled floor. If both shapes can exist, what triggers one pattern over another?A recent research study published in Current Biology examined the development of Drosophilas compound eye by comparing the wild-type arrangement of ommatidia with two anomalies that inhibit regulative developmental paths in the eye. These so-called small-eye mutations resulted in significantly fewer ommatidia and therefore required each ommatidium to move further to reach its neighbor, resulting in four-sided patterns to fill the space.