Null Glyphs

Across the games, there are a number of glyphs/symbols used in association with the Null. The exact symbology seems to vary from game-to-game, but there are a few which are reoccurring and can be said to have meanings. Each game seems to introduce at least one new symbol to the series, many of which are variations on known geometric patterns, such as Metatron's Cube.

Different symbols would appear to have different properties, though the nuances of the differences between them are still unknown.

Symbols used to contain Maggy's soul within the fortune telling booth at Grey Holm.

Major Symbols

Symbol	Seen in	Notes
Symbol in The Room: Old Sins.	TR TR2 TR3 TROS TRADM	There appear to be two variations of this symbol: one with extra detail in the doorways, and the other without. This pattern has some connection to doorways and the Null itself, and is one of the most prominent in the series.
The symbol as seen in the protagonist's journal, The Room Three.	TR TR2 TR3	This is implied to be derivative of constellations, or else certain constellations are seen to be derived from this symbol. The symbol is another variation of Metatron's Cube. The protagonist of the trilogy associates this symbol with the doorways, suggesting it may be related to interdimensional travel. Basis for the design known as the Null frame which holds the Null sample seen in The Room.
Symbol on a shield, The Room.	TR TR3	One of the constellation set. Not used as frequently as the other two hexagonal patterns, but is also a variation on the same root pattern. Used often in conjunction with the other two.
Metatron's Cube Metatron's Cube as it appears on the back of the Tarot Cards.	TR2 TR3 TROS	Many symbols in the series are derivatives of this pattern in some way.

Symbol Sets

Set	Appears in	Notes
Blue Symbols	TR TR3	Found around the safe in AS's Manor. Same symbols are found in the binding circles surrounding Maggy's tarot machine and are gradually added as she resists The Craftsman's attempts to contain her.
Combination Symbols	TR TR2 TR3 TROS	Frequently used in combination codes.
Constellation Symbols	TR
Crypt Symbols	TR2	Symbols seen in The Crypt.
Montfaucon's Symbols	TR2	Symbols seen in The Lab.
Null Planet Symbols	TR3	Symbols found along the walls of the temple maze in The Observatory. Originated on Mars. Some of these symbols are used to unlock puzzles within the model Greyhenge section of the Lighthouse level.
Waldegrave Manor Symbols	TROS	Symbols representing each room in Waldegrave Manor. Each symbol appears on its room's respective seal. The Attic symbol is one of the recurring major hexagonal glyphs.