In many developmental systems, the patterning of an undifferentiated pool of cells into an organized structure is achieved through the production of secreted morphogens that establish gradients of signaling activity that coordinate cell movements and specify distinct cell fates. Christine Thisse and colleagues now show that opposing gradients of two such morphogens, Nodal and bone morphogenetic protein (BMP), are sufficient to organize uncommitted zebrafish blastula cells into a well-patterned embryo (Science 344, 87–89, 2014). To establish the role of these morphogens, the authors generated opposing gradients of Nodal and BMP by injecting their respective mRNAs into different blastomeres at the undifferentiated animal pole of the zebrafish blastula. Whereas Nodal alone induced a radially symmetric structure with dorsal identity, the introduction of a gradient of BMP opposite to the Nodal gradient induced a bilaterally symmetric secondary body axis that was independent of the orientation of the primary axis. The authors repeated these experiments using explants of animal pole cells cultured in vitro and again found that opposing gradients of Nodal and BMP could produce a complete embryonic axis, showing that the activity of these two morphogens is sufficient to organize the basic vertebrate body plan.