N'ime ihe kacha mkpa Parameshvara nyere bụ usoro ya maka ụdị uru dị n'etiti maka ntụgharị ntụgharị nke sine. Ọ bụ onye mbụ na-agụ mgbakọ na mwepụ iji nye okirikiri okirikiri nke nwere akụkụ anọ. A na-ekenye Lhuilier (1782), afọ 350 mgbe e mesịrị. N'akụkụ akụkụ anọ nke cyclic bụ a, b, c, na d, okirikiri okirikiri nke okirikiri ahụ bụ: Ajụjụ: onye chọpụtara okirikiri ahụ?
Lhuilier