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Draw one of the waves, taper it with a warp, position it. Rinse repeat for every line. Then cut off the overlapping ends that you don't need.
Is there a specific tutorial
Draw a straight line
Use the zigzag effect to make waves
Use the transform effect to make copies
Cut off the the front, so all lines begin at the same x location
Make an art brush out of it
Apply to a straight line
Apply a width profile to it that enlarges it at one side.