Knitting the border that runs around the whole garment did get mind-blowingly tedious in the long run, I must admit, but it's a wonderful finishing touch that I wouldn't have wanted to leave out. Some things are definitely worth the perseverance it takes to make them.
The cape is very light, perhaps 120 grams of the 350 grams I bought. What to do with the remaining yarn? Well, after knitting several lace shawls of different shapes, some with and some without modifications, I think I'm ready to try designing my own lace shawl! I really liked the shape that consists of three triangles, so it will be one like that.
While knitting another shawl last month I thought the patterns resembled rain and flowers, so I'm working with that idea. (That is, until I change my mind.) There are drop-like pattern shapes of different sizes to begin with and my plan is to fill next border with flower shapes of some kind.