USB powered string of LEDs with clever current sharing trick.

I bought these as a convenient source of long parallel arrays of LEDs suitable for hacking into outdoor solar lights. I was expecting it to be just a USB plug, resistor and the parallel string of lights, but it turned out quite intriguing.
Firstly, the current was higher than expected at 800mA (8mA per LED) and there's no resistor!
Further investigation found that three wires were used along the run so that the positive side of the array was fed from one end and the negative side of the array was fed from the other end. This has two functions. The combined resistance of the feed and return wire to the far end acts as the resistance, and this arrangement results in even brightness along the full string instead of being brightest at one end and tapering off along the string due to the increasing resistance and voltage drop.