come from the caller's use of "patter" — a set of rhyming words and rhythms that complement the names of the dance steps being called. Patter can not only be entertaining because it is innovative and surprising, but it can also fill in the space between lengthy dance patterns, helping boost up the energy during potentially dull moments. There is a large, common pool of patter which callers might use. Examples are: Allemande left with your left hand. / Back to the partner for a right and left grand. OR Ace of diamonds, Jack of spades / Meet your partner and all promenade. The square dance calls are underlined; all the rest is patter. Many callers spend time inventing their own unique patter or variants on common patter. Entertainment also comes from callers challenging the dancers on the floor. There are many techniques to accomplish this. This can be done choreographically, for example, by mixing dance calls in unexpected or unusual ways, by varying expected dance patterns, or by calling figures from unusual and unexpected formations. Callers might also use gimmicks such as calling a common and well-known sequence of calls, and then catching dancers off guard by suddenly changing an expected call. Occasionally callers make mistakes, or forget what they are doing momentarily, in which case, it is important for them to be able to keep the dancers moving and to bring the dancers back to their partners, and home again, smoothly, and hopefully without anybody noticing. Call types There are two primary classifications of figure types in modern Western square dancing, patter and singing. Patter calls Patter calls, also known as hash calls, are based on a quick and fluid succession of spoken ("pattered") or sing-song delivered calls, often to the accompaniment of an instrumental piece of music that it is not necessarily recognizable as a song. Choreography may appear "on-the-fly" with calls randomly strung together, but it conforms to strict choreographic rules. Most patter calling is improvised by the caller as the dancers are moving; if the tempo of the calling is done at a fast pace allowing the dancers to flow from one move to another without pauses, it may be called hot hash. The primary purpose of patter calls is to give dancers a challenge by surprising them with unexpected choreography. Many callers are very well known for their ability to put calls together to