This is how you design the balls:
Protect your workstation with a VBS handicraft mat. Take an old container and fill it with lukewarm water. Test whether your plastic balls fit into it.
For each marbling process, add a few drops of colour for marbling in your desired colours to the container. Use a bamboo skewer to draw a pattern as desired. Plug your plastic balls onto the matching round bars and dip the ball into the water with a slight twisting motion. Pull it out and place the stick with the ball in the flower arrangement foam to dry.
Finally, you can knot satin ribbon around the socket of the ball.