Change some button shape to hexagons

[Bachibouzouk]

          <img width="514" alt="Unbenannt" src="https://user-images.githubusercontent.com/70587431/212695519-e7dfcffd-c0a5-41b4-a736-76460acc0f8a.PNG">

That's just a sketch. the forms of the energy cells on the website are a little bit different. If we change the buttons like this, the shapes of the cells should look similar.

Originally posted by @FredericHirschmueller in #18 (comment)

[Bachibouzouk]

@FredericHirschmueller - I set the priority for this one to low, feel free to update it ;)