sentence2_structure: An object<>attached<>$$$a spring<>sliding<>on a frictionless surface$$$An object attached to a spring<>is<>an uncomplicated type of simple harmonic oscillator
sentence1: This kind of wave pattern is called periodic waves, and its movement is also classified with oscillating springs as simple harmonic motion.
sentence2: An object attached to a spring sliding on a frictionless surface is an uncomplicated type of simple harmonic oscillator.
question: An object attached to a spring sliding on a frictionless surface is an uncomplicated type of what device?