Undulate (wavy/ripple) makes me think of
1. The pahoehoe lava that dries in long rippling waves at Kilauea (Hawaii Volcanoes National Park)
2. The long, smooth ripples on the lake, caused by the wake of passing boats, becoming gentler as time passes and they reach the shore

3. The lap-lapping sound of waves on the shore of the lake, whether caused by boats or wind – it is a soothing sound
4. Sunlight dancing on the tiny ripples of a lake in late afternoon
5. The wavy lines on a piece of wood, made by a tree, each section unique – found in rustic built cabins where the smell of the wood still permeates the air
6. Dreams: an image that comes closer and closer, then begins to fade away, each image like a long wave.
7. Music based on dreams, a sound beginning soft, almost unperceivable, grows louder and louder, then fades away – like the sound of a train that approaches, passes, and fades away, the sound growing fainter and fainter
8. Tall grasses blown by a gentle breeze; waving back and forth, or causing a ripple to travel over a prairie field
9. Meditating: colors or abstract images that undulate across the consciousness that I see behind my closed eyelids
10. A smooth dance – the dancer’s body undulating as it moves, the ripple of a flowing skirt or ribbons attached to the dancer’s costume

11. The ripple of a layer clouds brightly colored by a sunrise

I wish I had pictures of all of them, but although I have seen or heard each of them, I have no photographic record – they are imprints on my mind. Those that I have taken pictures of appear in this post.