x1 (number) is the minute/minute notation of the hour, of event/state x2, in system x3.
cacra zei mentu zei tcika. As default, the number x1 is counted from the first minute of the hour. See ti'u'e for BAI. ex.) li cino cu cacryme'utcika lo nu mi ti xrukla kei py sy ty (I will be back at thirty minutes past the hour PST.)