How something repeats, set in plain controls and said back in a sentence: every N days, weeks, months or years; which weekdays; in a month, on a date or on the second Tuesday (or the last Friday); ending never, on a date or after a number of times. The next dates are listed so the rule can be checked against a calendar, months without the chosen date are said, and the rule comes out as a value and an iCalendar RRULE. (Beamline complete system)