Takes 2 minutes in Illustrator. Try this:
1. Draw a grid of checkered squares, 2x2, 8x8, etc. depending on the scale you want the waves to be.
2. Effect > Warp > Flag > 5-10% or so
3. Object > Pattern > Make
4. Adjust the height setting for the pattern so it matches the width. It starts off a bit higher due to the height of the waves.
That's it. You're done.