Example-LateralSignalingReference:
Walter de Back, Joseph X. Zhou, Lutz Brusch, On the Role of Lateral Stabilization during Early Patterning in the Pancreas, Roy. Soc. Interface 10(79): 20120766, 2012.
http://dx.doi.org/10.1098/rsif.2012.0766
1((th / (th + a*Xn^n)) - X) + rand_norm(0.0,noise)(((th + b*(Y * Yn)^n) / (th + c*X^n + b*(Y * Yn)^n)) - Y ) + rand_norm(0.0,noise)tau == -1 and (X-Xn) > 0.05t