5 years ago I've learned this weaving method with paper. I thought it could be good with ribbon as well. And it works! :-) yuheeeee
The lenght of the ribbons dipend on what size is the gift box what you want to use for.
You always work with shorter pieces those will give the shape of the flower, the longers are for bind to the box.
If shorter pieces started to slide apart when you are ready, fix them to longers with double sided sticker!
Good luck :-)