x1 is the PA-th date/time of unit x2 (si'o) counting from x3 (default: now) by calendar x4
x3 is the reference point in time (PA = no). The splicing method depends on x4. For example, at 14:03 on 2014-11-14, the 0th day (x2 = lo si'o djedi) from now is 11-14, the 0th century from now is the 21st century, the 0th month (x2 = lo si'o masti) is November, the 0th afternoon is this afternoon (x2 = lo si'o donri), the 0th night (x2 = lo si'o nicte) refers to nothing (because this time-point is not in night).