1Cortical convolution patterns with different growth speeds (gs/gc). Numbered arrows indicate the corresponding locations on the cortex. In the first row (a–d), no growth difference is set to the cortex while in the second row (e–h) the cortex regions highlighted by the even numbered arrows grow faster than those highlighted by the odd numbered arrows . Based on observation, blue arrows are used to suggest sulcal regions and black arrows to suggest gyral ones. The simulation results shown in each sub-figure occur at the same simulation time.