The length and internal structure of Peking-opera plays is highly variable. Prior to 1949, "zhezixi", short plays or plays made up of short scenes from longer plays, were often performed. These plays usually center on one simple situation or feature a selection of scenes designed to include all four of the main Peking opera skills and showcase the virtuosity of the performers. This format has become less prevalent in recent times, but plays of one act are still performed. These short works, as well as individual scenes within longer works, are marked by an emotional progression from the beginning of the play to the end. For example, the concubine in the one act play "The Favorite Concubine Becomes Intoxicated" begins in a state of joy, and then moves to anger and jealousy, drunken playfulness, and finally to a feeling of defeat and resignation. A full-length play usually has from six to fifteen or more scenes. The overall story in these longer works is told through contrasting scenes. Plays will alternate between civil and martial scenes, or scenes involve protagonists and antagonists. There are several major scenes within the work that follow the pattern of emotional progression. It is these scenes that are usually excerpted for later "zhezixi" productions. Some of the most complex plays may even have an emotional progression from scene to scene.