Things You'll Need
Instructions
Set the tennis ball on a cup. A paper cup is often the best option, but a regular cup will work just as well. Make sure the cup is large enough that the tennis ball does not roll, but not so large that it will fall into the cup.
Looking at the picture of a Pokeball for reference, paint a black circle in the middle of the ball. Make sure to avoid filling in the circle. It should be as close to the middle as possible. The circle is small, about the size of a medium to large button. From the middle of this circle, paint a black line around the tennis ball. It should span the entire tennis ball and come around to the other side of the circle. Make sure this line is fairly thick. Be careful not to cross this line through the circle.
Paint the top of the tennis ball red.
Allow the top to dry, and then flip the tennis ball over to the other side. Paint the bottom of the tennis ball white.
Allow the white paint to dry. Paint the middle of the small circle white.