In this meditation with Thich Nhat, he talks about teaching children in France a walking meditation. When they breathe in, he teaches them to take three steps and say, "Oui, Oui, Oui." When they breathe out, he teaches them to say, "Yes, Yes, Yes."
Say yes to life, say thank you to the Earth.
Another quote from this meditation I love, "When we touch the sky with our eyes, touch deeply."