Let the Circuit Be Unbroken

Long ago, when the earth was young, Christmas lights were wired in a series.  What this meant was that, if one light burned out, the entire strand would not light because the circuit was broken.  Your task then would be to identify the derelict light, and remove it, replacing it with a (theoretically) good bulb.  This process could take hours, days, weeks... because, of course, there could be two bad bulbs, or three, or all.



These lights, wired in a series
Give me attacks of the wearies



'Cause you're making wiring queries
'Til your eyes are red and blearies.



But, when finished with all theories
And they light up like these here-ies,



You'll forget your gloom and drearies
'Cause the lights look oh, so cheeries.
 



All the earrings in this series
Would look fun and also cheeries.



And, if you have any queries,
Check right here, my clever dearies.