Abstract: An LED light string employs a plurality of LEDs wired in a series-parallel block. Further, each series-parallel block may be coupled in parallel, the parallel connection coupled across a supply voltage through an electrical interface. LEDs of the light string may comprise either a single color LED or an LED including multiple sub-dies, each sub-die of a different color. LED series-parallel blocks of the light string may be operated in continuous, periodic or pseudo-random state. The LED light string may provide polarized connectors to couple LED light strings end-to-end and in parallel with the supply voltage. The electrical interface may have one or more parallel outputs and a switch so as to operate multiple LED light strings in continuous, periodic or pseudo-random states. The LED light string may be adapted so as to employ LEDs of different drive voltages in each series section of the series-parallel block.