A biological examples of intrinsic control of size, shape and directionality of microtubule spatio-temporal pattern by synergistic-topological mechanism. A. Polarized epithelial cell (Schroer et al. ); local GTP-tubulin depletion and local cross diffusion are equilibrated. B. Microtubules intrinsic induction of cortical polarity in fission yeast (Schizosaccharomyces pombe) (Siegrist and Doe ); the cross diffusion stabilization effects overwhelm the depletion effects. C. Microtubules intrinsic induction of cortical polarity during fibroblast migration (Siegrist and Doe ); depletion effects overwhelm the local cross diffusion effects.