'Castells' can be divided into three parts. The pinya is the base of the 'castell', the group of people who are in touch with the ground with their feet and exert pressure towards the core, while serving as a cushion in case of a fall. The 'tronc' is the central part of the 'castell', the people who can be seen above the 'pinya' or base. Finally, the 'castell' culminates with the 'pom de dalt' (the upper part of the structure, formed by kids and which always adopts the same arrangement: two 'castellers' holding arms (called 'dosos'), another one squatting onto his shoulders called 'aixecador' or 'acotxador' and the last one, who must reach over and raise his hand symbolically (known as 'enxaneta').
The different types of 'castells' that exist are initially based on the combination of two parameters: height (the number of storeys) and width (the number of 'castellers' on each floor). These two parameters also determine the name given to each construction: thus, for example, a 'quatre' (four) 'de vuit' (eight) is an eight-storey construction that has four 'castellers' from the base to the fifth floor and with the three remaining floors that make up the above-mentioned 'pom de dalt'.
As for the width, the most common 'castells' range from two to five people per floor. Constructions with only one person per floor are called 'pilars'. Of course, they do not have the same configuration and are usually executed at the end of every performance and, sometimes, also at the beginning, as well as in formal and similar events. They are given a greeting value. There are also 'castells' with a more extensive base. In these cases, they are complex 'castells': two or more structures of two, three or four that add up, with differentiated 'poms de dalt'. Complex 'castells' are also those that are built with a 'pilar' (or 'agulla') inside. That is, a single-storey castell inside of the main construction.
Regarding height, the smallest 'castells' have six floors and structures of up to ten floors have been built. Pillars are the exception, with up to… nine floors! In taller constructions, a second, third or even fourth base can be added on top of each other, called 'folre' (when located on the second floor), 'manilles' (on the third floor) and 'puntals' (on the fourth floor).
Finally, we must also take into account that there is a type of special 'castells' according to their execution technique, such as those raised from below. These are constructions in which the floors are raised by hand, with structures of up to eight floors (generally three floors per base) have been completed.
Of course, some constructions are more difficult than others. Generally, the higher a 'castell' is, the more difficult it is. But other factors must also be taken into account, such as the width (for example, a tres de vuit is considered more difficult than a 'quatre de vuit'), the execution technique or whether or not additional reinforcement bases are used. This is what allows us to establish a hierarchy of difficulties and, therefore, a table of scores, which is one of the elements that define the Concurs de Castells.
