In the fall of 1986, Eric Graham discovered that the Amiga 1000 personal computer, running at a meager 7.16 MHz, was powerful enough to ray trace simple 3D scenes. This is a recreation by coding from first principles.
a digital signal processing (DSP) technique for identifying frequency components of a signal, published by Dr. Gerald Goertzel in 1958. While the general Fast Fourier transform (FFT) algorithm computes evenly across the bandwidth of the incoming signal, the Goertzel algorithm looks at specific, predetermined frequency.