We have the Twinkly lights and they are pretty neat. You put them on your tree and you don't have to be careful about where or how you lay them out because step 2 is point your phone camera at the tree and it turns the lights on and off to map where each bulb is. You move around the tree until they are all mapped (lights go from orange to green when mapped).

The app has a bunch of canned patterns and there's an online site for user designs and of course you can design your own. It's a lot of fun and they aren't terribly expensive (there was a good black friday sale).