The 12 signs are divided into 3 groups of four. Each group is assigned a modality. Learning about the modalities can help get a better grasp of the traits of the signs individually. these groups are called quadruplicates, because there are 4 signs in each group.
Fixed Signs – Taurus, Leo, Scorpio, Aquarius
The Fixed Houses are the Second, Fifth, Eighth and Eleventh; if an astrological chart shows a preponderance of planets in these houses, its energy is weighted toward fixity.
The fixed signs experience frustration and temperamental reactivity. They can feel too full of energy and over excited until the state of anxious, and then become overly lethargic and self isolating. This is why their energy must be released with intention, or they often become trapped by compulsion and addiction, because a fixed sign will always return to what they know works.
According to Dmirti Popov of Astrology.com
Fixed Signs understand that steadiness is the key. Those influenced by this Quality are happy to forge ahead with their projects, calmly working away until they have achieved their objectives. This is no struggle for Fixed folks, rather it’s what makes them tick. These individuals are stable, determined and resolute. They want to get to the finish line and have the persistence and ability to concentrate, characteristics which will get them there.
There is no lack of confidence in Fixed individuals. Self-reliance could be a Fixed person’s middle name. Those possessed of a Fixed nature are powerful, yet purposeful. There are no wasted motions here: Fixed folks move patiently and steadily toward their goals. They are also steady and reliable and always remember those who helped them out. Conversely, those born under a Fixed sign can at times be stubborn, my-way-or-the-highway folks. They may have a tendency to get stuck in their ways and to believe that they are always right.
Those influenced by a Fixed Quality are determined, reliable and persistent. They have great strength, and strength of purpose, and love to get the job done. So what if they refuse to budge? They get results.
Cardinal Signs – Aries, Cancer, Libra, Capricorn
The Cardinal Houses are the First, Fourth, Seventh and Tenth; if an astrological chart shows a preponderance of planets in these houses, its energy is weighted toward cardinality.
According to Alice Donovan Rouse of Astrology.com
Cardinal Signs are the initiators of the zodiac. They are also found at key jumping-off points on the chart wheel, specifically the Ascendant, Medium Coeli (M.C. or Midheaven), Descendant and Imum Coeli (I.C.). Individuals possessing a Cardinal Quality like to get things going. They are active, quick and ambitious. Many projects get started, thanks to Cardinal initiative, although a good deal of them are never finished. That’s because Cardinal folks are much fonder of starting things than finishing them.
You won’t find a Cardinal person slacking off. These people are full of vim and vigor and possess a drive and ambition that is unmistakable. Enthusiasm and a zest for life fill the Cardinal individual. Some might perceive this rampant energy as domineering, and, at times, it can be. Cardinal people can easily forget about the rest of the pack when they are busily focusing on their own endeavors. Even so, their energetic spirit often wins the day.
Cardinal folks are clever and want to win. They love to start things, and whether they finish them or not, there’s always a lot going on. Naysayers who find them to be too self-centered will simply have to watch (and marvel) as they speed by!
Mutable Signs – Gemini, Virgo, Sagittarius and Pisces
A Mutable Quality is attached to the signs. The Mutable Houses are the Third, Sixth, Ninth and Twelfth; if a horoscope shows a preponderance of planets in these houses, its energy is weighted toward mutability.
Mutable signs take on the traits of the other signs in their chart. The traits of the other signs overshadow their own because mutable signs are a sponge. Their sun sign is a vehicle for their other placements.
According to Chris Barbalis of Astrology.com
Mutable Signs know how to go with the flow. They are adaptable and flexible and can change their form of expression to whatever a situation requires. Standing their ground is of little import to Mutable folks. These people would much rather conform to the norm, so long as their doing so will help the greater good. Luckily, Mutable individuals are versatile and find it quite easy to change. Consider them the chameleons of the zodiac, since they can take on varied personae.
Mutable people are blessed with a tremendous resourcefulness. Talk about making lemonade out of lemons! They know how to squeeze that last drop of juice and make things better in the process. Those influenced by a Mutable Quality in their horoscope also enjoy learning, play fair and are diplomatic and well-liked by others. To their further credit, they are sharp, sympathetic and can see (via a sixth sense?) the essential elements of a situation. At times, however, their desire to please everyone can get them into hot water. They may come across as wishy-washy, inconsistent and downright duplicitous. All this in the name of aiming to please!
The beauty of mutability is that those possessing it are flexible, versatile and highly resourceful. These folks are quick to help others and are selfless in the process. While they may occasionally stretch themselves to the breaking point, they know how to bounce back.