Njirimara ngwaahịa:
1/.Ogologo oriọna nwere ike ịbụ na 150mm, 200mm, 300mm na 400mm ma ọ bụ ahaziri.
2/.oriọna nwere ngwakọta nke isi 2/3/4/5 ma ọ bụ ahaziri ya.
3/.Ngosipụta arụmọrụ dị elu nwere akụkụ beam 18º/24º/36º/60º.

Ngwa:
Ụlọ oriri na ọṅụṅụ, cafe, ụlọ.wdg...


