Also that retains some kind of religion within the virtue of yantra plus the mantras associated with it. You should also bear in mind which the Yantra isn't a Device that may be intended for the maniping or hurting of some people. Lord Shiva discovered the mantra to Mata Parvati, https://vashikaran77417.blogoscience.com/41611218/5-simple-statements-about-mahavidya-explained