Symbolacron is the name of the second-most common archetype of Endbeing forms.
Physical features
Symbolacra have a central polytope as opposed to the central eye of an Arraphim. The polytope is known as the core, and is always symmetrical to a certain degree, but usually is regular, uniform, or the dual of a uniform. The polytope is surrounded by a symmetrical arrangement of irregular multiprisms pointing outwards, known as "glyphs". In odd dimensions, the glyphs are two side-by-side flat multiprisms of the previous dimension (technically slightly extruded into the new dimension since nothing is completely flat in any dimension). The 2D components of these multiprisms are typically Greek letters in serif or sans-serif forms, with both cases equally likely, typically the same two letters for all duoprisms. Occasionally other human scripts can happen though. It seems human writing systems in E3/Tuxe were influenced by the simulation overseers to match the Symbolacra.
The core has similar qualities to that of the Toriphan archetype. One facet opens into a mouth/vocal tract, while the other opens into the waste-expelling end, and the core contains all of the internal organs.
Also similar to Toriphans, the rings are bound to the core by an invisible, incredibly strong force. The force does not block things from passing between the rings and the core, nor does such an occurence interrupt the force or harm the Endbeing.
Symbolacra have telekinesis for picking up and using objects. For more precision, each glyph has a paltry few dozen millimeters of positional and angular leeway from its typical orientation, which can be controlled like an arm. This is likely why the glyphs tend to be letter-like, with lots of hooks and bends for grip. As for walking, they just roll in any direction in any subset of the six rotational planes, though double-rotation takes more energy than single-rotation since it requires both propulsion engines (a pair of core organs) to be activated rather than just one.
It's possible, though rare, for a Symbolacron form to have no working facilities to manually reroll their genetics, similar to most Arraphim forms.
Symbolacra lack vision organs and instead have an intrinsic sight sense that sees all angles around them as if it were projected to the inside of a hypersphere.
Gallery

A crude 2D representation of a Symbolacron with Uppercase-Sigma/Lowercase-Xi glyphs and a pentagonal icosatetrahedron as the core.

Outzschcrad, a Symbolacron scientist
Trivia