Have you seen the new craze?
Basically you slam together a button-battery (cr2032) and a bright LED, and tape them around with electric tape. If you want you can tape together a neodymium magnet as well and throw it on a lamp post or anything metal. Hence the name.
I thought I would copy the meme but instead of the magnets I used blue-tack to glue them on the balcony wall to serve as Christmas decorations.
It worked pretty well. Here are the results.