In chapter 23, Lucy and Elinor work on a “fillagree basket” for little Annamaria.
Fillagree is a rolled paper design, very time consuming to produce, fragile and thus, extravagant for a 3-year old who would likely ruin them in very little time. It’s another folly of Lady Middleton’s indulgence of her children. Below are two patterns for fillagree work as published in The New Ladies Magazine in 1786.
For some examples, I found these illustrations of 18th century paper fillagree work at Google images, linked here.
Note that JA spells it as “fillagree” and I can find this spelling in my go-to reference, dictionary.com. Google and Wikipedia want to correct the spelling though, and refer to it as filigree.