Complex sentence: In 1906, she experimented with an atypical format designing "Miss Moppet" in a panorama style, which booksellers disliked; the story was reprinted after 1913 in small book format.
Split into simpler sentences: In 1906, she experimented with an atypical format, and designed "Miss Moppet" in a panorama style. Booksellers disliked the format, and the story was reprinted after 1913 in small book format.