A three-dimensional array constructed from perpendicular Nematostella embryo views. A B) NvFoxB expression in the early larva appears focused on two spots around the oral pole (original images from ). Reference points are indicated as blue crosshairs on lateral (A) and oral (B) views to shift and scale the oral image’s height. In the original images, the black arrows highlight isolated expression in some endodermal cells. C) A coordinate sweep is performed over the three-dimensional array and the corresponding points S1 and S2 on the lateral and oral images, respectively, are determined. The point with minimal signal is selected for the new array P. Because the signal is darker than the background, the minimal signal corresponds to the maximal intensity, as expressed in the algorithm in figure 6A. D) The greyscale intensity is displayed in three perpendicular planes of the 3D gene expression array. The main features of the expression pattern in panels A and B can be identified in this representation (red arrow).