This example demonstrates how to combine multiple sine waves into a single signal and visualize the result. It generates three distinct sine waves at frequencies of 8, 15, and 5 Hz using a custom `sineGenerator` function, then sums them into a combined amplitude signal that is plotted as a line chart using D3's `scaleLinear` and `line` methods. The visualization includes labeled axes for data points and signal amplitude, with the chart rendered inside a gray rectangular region. While the code includes FFT utilities from the included `fft.js` and `fftutil.js` modules, the current view only displays the raw combined waveform rather than the frequency-domain analysis.