I hadn't heard of himmeli until my colleague O started making them. Two have made it into the garden, on one of the rowans. This is a bit about them from hemleva.com:
Originating from the Swedish word for sky or heaven, himmel, the Himmeli are a traditional Finnish ornament, a mobile decoration that is traditionally made out of straw, or reeds in Finland. They are typically extremely ornate and are suspended above the dinner table during the holiday season. It is thought that the larger the Himmeli, the larger the rye crop will be in the coming year. During the holidays, the dining room ceilings can be covered with these intricate mobiles.
There's more about them on the Etsy blog.
There are some instructions on how to make your own here.