Start with at least two colors of fondant. Roll the two colors into equal length logs.
Place the logs side by side and twist. Fold the log in half and twist again until the pieces begin to come together. Repeat the twisting and folding process 2-3 times, but do not overwork, or else the colors will begin to blend too much. Finish up by forming the kneaded fondant into a ball.
Roll out the fondant to see the full marble effect.
Hint: You can use more than one accent color to create more variation, but choose colors that contrast in order to see the marbling effect.