The light spectrum is usually drawn in a line........a painter's palette in a circle.........spin and gin......quantum physics and the Irish.............................are we going in circles?  Or over the rainbow...........wiz of Oz???

Washington Metro lines

Line Name	Opened	Stations	Distance		Termini
			mi	km	Western/Southern	Eastern/Northern
Red Line	1976	27	31.9	51.3	Shady Grove	Glenmont
Blue Line	1977	27	30.3	48.8	Franconia–Springfield	Largo Town Center
Orange Line	1978	26	26.4	42.5	Vienna	New Carrollton
Yellow Line	1983	17	15.07	24.25	Huntington Franconia–Springfield(Rush+)	Mount Vernon Square (rush hours) Greenbelt (Rush+) Fort Totten (other times)
Green Line	1991	21	23.04	37.08	Branch Avenue	Greenbelt
Silver Line	2014	28	29.6	47.6	Wiehle–Reston East Ashburn (opens 2019)	Largo Town Center