It's not always easy to understand what is meant by "Now" or "Present Moment Awareness" when practicing mindfulness meditation. People often think that paying attention to what's happening 'Now' means ignoring the past and the future. Of course, this isn't true, but it can be a confusing concept.
For years I couldn't find a visual way to show my mindfulness students how past, present and future are all part of the present moment -- until I taught a clinic for teachers in Singapore. It was there that one of my adult students stood up and told us how she used an apple as a visual aid and proceeded to relate a technique that was at once remarkably simple yet profound. After watching her demonstration, I bet none of her students thought of present moment awareness in quite the same way again.