In that in that case also only the hurricane dissipate, only when if hit is from the sea when it approaches the towards the land and approach a certain boundary. So, then it dissipate the energy dissipate dissipated and then we do not see any a vortex, the lose there identity the strength they lose their strength. So, this understanding approves to vortex lines and vortex tubes, now we will go to we will talk a little about stream lines and path lines.