Verb (used without object) : The flag undulates in the breeze. ,the wail of a siren undulating in the distance.    From Dictionary.com. 

Two flags were stiffly undulating from the halyards like squares of flexible sheet-iron.    From Wordnik.com.  [The Jessie] Reference

The Arabian desert has been closing up on the eastern bank for some time past, and now rolls on in undulating drifts to the water's edge.    From Wordnik.com.  [A Thousand Miles Up the Nile] Reference

The pitch is what can kindly be called "undulating" and has a significant slope from one goal to the other.    From Wordnik.com.  [When Is Second Best?] Reference

    At first Kamahl thought his friend was coated in some kind of undulating ooze, but as he looked closer, he saw the truth.    From Wordnik.com.  [Chainer's Torment]

The word "undulating" has been getting a workout this week.    From Wordnik.com.  [Tucson Citizen] Reference

After a long time, she ceased vibrating and undulating and gasping.    From Wordnik.com.  [Instrument] Reference

The Shadow tried to drown me beneath waves of undulating, liquid hate.    From Wordnik.com.  [The Shadow] Reference

I've heard that it can be a bit undulating, but am praying that won't be the case.    From Wordnik.com.  [London-Amsterdam by bike ? do I need Dutch courage or careful planning?] Reference

The motion of waves is rendered in huge undulating lines of color or plain white.    From Wordnik.com.  [Peter Clothier: ACE Gallery: Three Artists] Reference

The long, undulating high alpine climb has sections of sustained 12 percent gradient.    From Wordnik.com.  [For Burke Swindlehurst, the quiet American, the Tour of Utah may be a last hurrah] Reference

And undulating, firelike lights lick at the perimeter of the rotunda's giant skylight.    From Wordnik.com.  [Groping In The Dark] Reference

All Cuban music has that undulating two-bar rhythm, one bar straight, one bar syncopated.    From Wordnik.com.  [Diddley's Beat Ba-bomps into the 21st Century] Reference

Stop once the cream starts to feel heavy on the whisk and will lie in soft, undulating folds.    From Wordnik.com.  [Nigel Slater's classic gooseberry fool recipe] Reference

The undulating convex and concave design cues give this ragtop a more athletic, masculine vibe.    From Wordnik.com.  [Road Test | Bmw Z4] Reference

Kopaonik (kopaonik. net) has 21 lifts serving undulating intermediate runs, and a vibrant nightlife.    From Wordnik.com.  [TIP SHEET] Reference

Driven 173 miles, nearly the whole time in pretty, sparely inhabited, wooded, and undulating country.    From Wordnik.com.  [A Lady's Life on a Farm in Manitoba] Reference

The hills with their undulating skyline are dark – a sharply incised silhouette against the brightness.    From Wordnik.com.  [Country diary: Shetland] Reference

He compared it to naval warfare: a contest over undulating, trackless terrain as far as the eye could see.    From Wordnik.com.  [A Course At The 'College Of Rommel'] Reference

Lelani's breathing deepened and she began undulating gently, pushing his hand a little lower on her stomach.    From Wordnik.com.  [Instrument] Reference

The view from this perch was spectacular: an undulating carpet of green ridges and valleys in all directions.    From Wordnik.com.  [The Blessing And Burden Of Coal] Reference

The result, hopefully, will be undulating, hyphenated rivers of color flowing through a drab winter landscape.    From Wordnik.com.  [MANHATTAN PROJECT] Reference

Woods and fields were slumbering; the avenues in the park showed only as long, undulating, and undecided lines.    From Wordnik.com.  [The French Immortals Series — Complete] Reference

Cary swiveled the chair to show me the final result: large, smooth, undulating curls cascading over my shoulders.    From Wordnik.com.  [Emily Farache: Hair and Ego Part Three: Happy Client Equals Happy Me?] Reference

 It was all black, but he could see the bottom was undulating, shining with reflective black skin and undulating.    From Wordnik.com.  [What the Father Said] Reference

The part I loved the best was when he was inching toward her with those snaky, undulating pelvic back and forth moves.    From Wordnik.com.  [Tonya Plank: So You Think You Can Dance Week 7: Can it Be, a Week Without Injuries?] Reference

I precisely render the delicate folds of the floral hair pieces and the undulating waves of the smartly pressed tunic.    From Wordnik.com.  [Geisha Doll] Reference

The rain turned icy and we raced down undulating country lanes to the cobbled town of Candelario before hypothermia set in.    From Wordnik.com.  [Trans-Iberian: cycling Spain's ancient Via de la Plata] Reference

She smeared the walls with her hands to create an undulating background pattern, then outlined and painted trees and plants.    From Wordnik.com.  [The 'Other Masters'] Reference

Against the backdrop of the blaring music and undulating spotlights at Fashion's Night Out, Georgetown was anything but dull.    From Wordnik.com.  [Georgetown's retail landscape starts to rebound from recession] Reference

He was just so on with the styling, those hands were perfect, the kicks, the feet, the rhythmic, undulating mid-body movement.    From Wordnik.com.  [Tonya Plank: So You Think You Can Dance Week 7: Can it Be, a Week Without Injuries?] Reference

For filmmaker George Lucas, it's just another noontime in the undulating hills of his high-tech paradise north of San Francisco.    From Wordnik.com.  [The Force Of An Idea Is With Him] Reference

Turn a corner in Rio, Belo Horizonte or So Paulo, and you are likely to come face to face with one of Niemeyer's undulating creations.    From Wordnik.com.  [Skyline Sculptor] Reference

And this week, the New York Yankees will hold "" Macarena Night, '' challenging the previous record of 37, 576 undulating Mariners fans.    From Wordnik.com.  [Blame It On The Macarena] Reference

Of what then, was the will of man made, undulating like the sea, and variable as the wind, that he had the folly to believe his was firm?.    From Wordnik.com.  [The French Immortals Series — Complete] Reference

Not a star or a plane but what looks now to be a ring of undulating lights, moving in a weird circular motion, like a crooked Ferris wheel.    From Wordnik.com.  [13 Halloweens] Reference