Sprite Stitch Board!

Hey everyone. I am looking to make a portal cake stitch. I need it pretty simple and only 20 x 20 stitches, around 5 colors. I tried to make a pattern but I think the fact that its round is throwing me off. I am including a picture of what I want it to look like. Thanks to whoever can help me!

20x20 is just too small. the best i've found is a cake thats 34 stitches wide on this image:



its not coloured, but that's easy enough to do if you want it.