Visualize a beautiful rose in the center of your chest. It is not necessary, when doing this exercise, to see a clear picture of the rose. Simply do the best you can to imagine a soft, reddish rose in the center of your chest. If other thoughts and images pass through your mind while you are performing this exercise, simply ignore them.
Imagine that the rose is completely folded up; none of its petals have yet unfolded. Now, as you focus your attention on the reddish rose in the center of your chest, visualize that the first set of petals, the outer row of petals, is gradually unfolding. As they do so, imagine them growing and expanding and filling the entire area of your chest. Simultaneously feel a wave of peace and joy spreading throughout your entire chest area.
Then visualize that a second set of rose petals is unfolding. Imagine them slowly and gently unfolding and expanding, this time filling the entire area of your body. Imagine another wave of peace and joy, even deeper than the first, starting in the center of the chest, in the center of the rose, and expanding outward, filling your entire body with peace and joy. Now visualize a third set of petals, again starting in the center of the rose, and imagine them expanding outward, filling up the entire room, spreading peace and joy everywhere throughout the room or area in which you are meditating.
Then visualize a fourth set of petals opening up, this time expanding and filling the entire earth. Feel that peace and joy are spreading from the center of your chest, from the center of the rose, throughout all of the earth and filling all of the people and all of the beings and all of the objects on this earth with peace and joy.
Now visualize another set of petals opening up, this time filling the entire solar system with peace and bliss. Simultaneously feel that you are spreading your own inner peace, of which you have an infinite supply, throughout the entire solar system.
Finally visualize that a sixth row of petals is opening up, this time filling up the entire universe, spreading peace and joy throughout the universe and on into the infinite.
As you practice this exercise, continue to visualize additional petals of the rose unfolding. As each set of petals unfolds and spreads out into the infinite, feel that they are reaching farther and farther out and spreading a deeper peace and joy throughout your whole being and throughout all of existence. There is no end to the petals of the inner rose. Continue to unfold set after set of petals until you have completed your meditation session.
-Excerpted from Snowboarding to Nirvana by Frederick Lenz