Within these headings, the alloys are also grouped alphabetically. Ships are grouped by type, and listed alphabetically within. Philosophical questions can be grouped into categories. As with the other principal ranks, Classes can be grouped and subdivided. These techniques were loosely grouped under corresponding natural elements. Qualifications are grouped together into different levels. The early groups are grouped together as Labyrinthodontia. Galagos are currently grouped into six genera. However, multiple iCalendar objects can be grouped together. Generally, data can be grouped according to several observed factors. Rooms are usually grouped together, as are lockers. Similarly, adjectives are often grouped in threes to emphasize an idea. Within a deployment, objects are grouped into domains. Circuits are grouped together to form Districts. They can generally either be grouped as annuals or perennials.