The angle to the horizontal my be between 0 and 90 degree and one spring may be missing.
While nothing in the real world truly has zero damping, a good example, though it doesn't use a coil spring would be a tuned mass vibration absorber.
It's basically a mass attached to a motor, or another vibrating object by a stiff rod. By varying the amount of mass and the stiffness of the rod, the absorber can be "tuned" to have a natural frequency matching the dominant frequency of the motor's vibration. (For most electric motors driven with 60Hz AC, this will be 120Hz)
When the motor runs, the 120Hz vibration of the motor will drive the absorber at resonance instead of driving the attached structure which would create noise.
While these absorbers are similar in concept to the "Tuned Mass Dampers" seen in large buildings, a tuned mass absorber does not require damping to function.
Here's a nice explanation from Penn State
Pedagogically speaking, oscillating systems are part of the engineering environment. We need to recognize, accommodate, and sometimes mitigate their effects more so than design and construct them. Harmonic oscillation is an analysis tool, not a design tool.