​This simulator calculates the phyllotaxis pattern of sunflowers. New seeds add at the center of the flower, and old seeds gradually go away from the center. As the outer most seeds move slower than the inner seeds, the packing effect occurs to make the seeds draw up in order, the Fibonacci spiral. 

Reaction-diffusion simulator web-version. You can play the RD simulator with your PC or smartphone. Enjoy!

This program generates the 3D shape of seashells, clams, and horns of goats. The basic idea is explained in ​​https://link.springer.com/chapter/10.1007/978-1-4757-9153-2_8

KTmodel is a simplified version of the RD model. In the RD model, the diffusion rate of two molecules determines the relationship between distance and strength of activation (suppression). On the other hand, in the KT model, the relationship between distance and strength of activation (suppression) can be directly inputted as the shape of the kernel. This simplification allows the KT model to be applied to systems where the signal is not transmitted by diffusion.