You need -
- Styrofoam tray (the ones you get with veggies or fruits)
- paints & paintbrush
- clear varnish
- Paint the tray with a thick coat of purple and allow it to dry.
- Next, paint big pink spots.
- Finish by highlighting with bright yellow dots and applying an even coat of clear varnish.
As simple as that! Of course you can try different colours and patterns. A word of caution though - styrofoam is quite fragile, so you need to be careful with it!