Let's consider a plane wave of the form $e^{i(\vec{k}.\vec{r}-\omega t)}$

Is the graphical representation the following 

[![reference : https://fr.wikipedia.org/wiki/Onde_plane][1]][1]

or the following ?

[![enter image description here][2]][2]

I'm wondering what is now the graphical representation for the case of a plane wave of the form $e^{i(k.x-\omega t)}$ ?

Is it just that ?

[![enter image description here][3]][3]

or is it that :

[![enter image description here][4]][4]


  [1]: https://i.sstatic.net/AeuGg.png
  [2]: https://i.sstatic.net/bwGVl.png
  [3]: https://i.sstatic.net/3492d.png
  [4]: https://i.sstatic.net/c465A.png