In order to accentuate the Marian dimension of the Blessed Sacrament, Abbot Armand-Jean de Rancé replaced the tabernacle in La Trappe with a statue of Our Lady holding a pyx containing the Eucharist. The abbot wrote an inscription highlighting the honor of Mary bearing God. Some found it shocking, but defenders claimed it was an ancient Cistercian tradition, although no one has been able to confirm that.

The theater publisher Albert Langen / Georg Müller in Berlin used a cheap but charming cover for low-budget scripts, like this play (Onkel Theodor by Selma Lagerlöf). 

By simply opening the cover, readers noticed that it had a window in the style of a stage. The effect was a little like the curtain rising in the theater. These covers were applicable to any play, since the title of the play was printed on the title page which, originally, seemed to be part of the cover. 
Other publishers used this technique in more prosaic ways, e.g. for the cost-efficient publication of dissertations.