A composite array has two two-dimensional arrays on a substrate each having two rows of LEDs. The LEDs in each array have the same orientation as all other LEDs in that array. First electrical traces sequentially couple LEDs in the first string and the second string by beginning at opposite corners of the composite array and alternating between rows of each of the first and second arrays. A second electrical trace couples ends of the first and second strings across rows of the composite array. Third electrical traces route outside the composite array and are coupled, respectively, to a beginning of the first string for the row of the composite array containing the beginning of the first string, a beginning of the second string for the other row, the end of the first LED string for the other row, and electrodes of LEDs in the other row.