Z-curve theory provides a very unique geometrical approach of analyzing a genetic sequence, while preserving all the genome information. In this computational essay, I've developed a very efficient and fast function (in the Wolfram Language) to generate the Z-curve of any genetic sequence, regardless of its length. Then, I generate Z-curves of 39 COVID-19 viruses together with 40 SARS-like viruses, using their complete genomes. Numerical analysis of corresponding Z-curves and their clustering show a very close phylogenetic relationship between family of COVID-19 viruses and Bat coronavirus isolate RaTG13 (MN996532), therefore supporting the hypotheses of a Bat origin for the COVID-19.