The mani mantra can be used to resonate major centers, as shown below. The sound can be done vocally, or externally silent yet still resonating inside, internal sound. The sanskrit syllables can be visualized within the deep-centers, as described in the basic process of the enso essay, not only as a focusing tool but also with the added refinement benefit of resonant sound. The visualized syllables become tuning forks of a sort.
This basic approach is common within the vajrayana practices of Tibetan Buddhism, and is often an aspect of deity yoga. The mani mantra is associated with Kwan Yin (spellings vary), who is popular throughout the eastern religions and is considered an aspect of Avalokitesvara in Tibetan Buddhism.
Below are several images that maybe of some help, and are suitable for printing.
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