 There are as many such paths as there are pins used to control the array minus 2; if the LED with anode at node "m" and cathode at node "n" fails in this way, it may be that every single pair of LEDs in which one's anode is node "m", cathode is "p" for any value of "p" (with the exceptions that "p" cannot be "m" or "n", so there are as many possible choices for "p" as the number of pins controlling the array minus 2), along with the LED whose anode is "p" and cathode is "n", will all light up.If there are 8 I/O pins controlling the array, this means that there will be 6 parasitic paths through pairs of 2 LEDs, and 12 LEDs may be unintentionally lit, but fortunately this will only happen when the one bad LED is supposed to come on, which may be a small fraction of the time and will exhibit no deleterious symptoms when the problem LED is not supposed to be lit.If the problem is a short between nodes "x" and "y", then every time any LED "U" with either "x" or "y" as its anode or cathode and some node "z" as its other electrode is supposed to come on (without loss of generality, suppose "U"'s cathode is connected to "x"), the LED "V" with cathode "y" and anode "z" will light as well, so any time EITHER node "x" or "y" is activated as an anode OR a cathode, two LEDs will come on instead of one.