i, ri, u, li

i, ri, u, li, The Vimalaprabha explains that these letters are to be written one on top of the other, and strengthened, so that the letters "li", "u", "ri" and "i" become "la", "va", "ra" and "ya". They then form the Kalacakra monogram, "hkshmlvryam", with "ksha" being written below and to the left of "ha", then "ma" below and to the left of "ksha", and so on. http://www.kalacakra.org/namcu/namcu01.htmhttp://www.kalacakra.org/namcu/namcu01.htm