I decided so after seeing a picture on facebook and because I'm kinda bored during holidays. Here's how I want it to look like:

Sadly, I don't know how the recipie! Sure, I've helped making cakes so I have some experience, and want to get the best possible dough that will make the cake feel moist and fresh.
There is also a problem, I'm kinda afraid that the cake is going to be really dry and taste bland, so I was thinking of applying a thin layer of jam over every color, just like a zacher cake or maybe I could add something to the dough.
So yeah, if anyone has experience with such things, a recipie or some videos would be nice, especially because of the measurements.
I will post results in about 3 days from now.
And I won't be using any cake mixes or whatever, we don't have those at my local supermarket. Also don't suggest adding weed because my family is going to eat it too.