"Now, there's something wrong with this..."

...she wondered while happily stitching away Ezmeralda's House.

Any guesses what she screwed up?

"For Pete's sake! Why the h**l I've been stitching with two strand when I've started this with one strand?! [insert some nasty words here]"
Then our heroine took her trusted seam ripper and frogged every single stitch she had stitched today, just to begin it all again. At this time with a single strand of floss...