Shapes in magick:

Circle: The sun and moon, enlightenment, unity, wholeness, infinity, perfection, ideals, protection, containment, gods/deities, rebirth and completion, and the element of spirit

Triangle: The triangle is heavily associated with the power of three, and ergo the following concepts/rules:

Birth, life, death

Past, present, future

3 stars on Orion’s belt

Hear no Evil, See no Evil, Speak no Evil

Liberty, Equality, Fraternity

Beginning, middle, end

Sunrise, noon, sunset

Body, mind, heart

It is also associated with summoning symbols. Orientation matters just as much as the actual shape when it comes to triangles, as a point-down triangle symbolizes femininity, earth and water, goddesses, and the decent into the physical world. Meanwhile a pointed-up triangle represents stability, foundation, air and fire, energy flows, ascents into the after life/spiritual realm, and masculine elements.

Square: associated with the number 4, it is a nod to the main compass directions, the physical elements, seasons, solidity, static perfection and dependability, and the material world in general. In many other cultures the square also generally means order, safeness, and a square in most cultures is a meeting place or plaza at the heart of a city (ie town square, etc.)

Spiral: relating to circles, it is one of the oldest geometric shapes and associates with the achievement of the altered states of consciousness

Infinity: the infinity symbol represents reincarnation, lessons/knowledge, the maternial plane, the karmic circle a calling to wake up and rise, and derives from Uraeus, which is a magical cobra found commonly in ancient Egypt records and means either “the coiled one” or mehet, or “the risen one” or iaret, but both times the snake is depicted in this position.

“What very few people discover (or remember) is that the symbolism of the Infinity comes from the great Uraeus, symbols of the Goddess Wadjet… What this symbolic act represents, is that one will never have true power until s/he realizes the divine power within.” - 5 Surprising Secrets of the Infinity Symbol ∞ by Mind Journal

Stars(5 pointed): also called a pentagram, the five pointed star represents the five human elements (air, earth, fire, water, spirit) and it is a symbol of protection and warding in many cultures, including wicca, which witchcraft takes the heaviest influence from. While many see the pentagram as satanic, what they tend to forget is that a five pointed star is a type of pentagram, but the lines in the center of the pentagram tend to be left in. Similar in design is a pentacle, which in merely a pentagram with a circle added around it, but in general they are all similar in design concept.

https://www.learnreligions.com/geometric-shapes-4086370#step-heading?utm_source=pinterest&utm_medium=social&utm_campaign=shareurlbuttons_nip

https://themindsjournal.com/secrets-of-the-infinity-symbol/#:~:text=1.,symbols%20of%20the%20Goddess%20Wadjet.&text=During%20the%20coronation%20of%20the,crowned%20by%20this%20divine%20snake.

Source: Punkylilwitch