Tepatic glyphs originated in pre-Tepatic Milim times as images, such as those found in Milim rock paintings. Presumably, all of the glyphs used in Yuk Tepat originated as pictures - either depictions of things, or iconic representations of concepts. Although many glyphs have been stylized to the point that their appearance does not immediately suggest their meaning, they still continue the image of something, and in that sense are “representational.”
Some cases are metonymic - a picture of a part stands in for the whole. For example, the glyph for nap ‘man’ was originally just a stylized penis, the most important part of a man.
Sometimes the image is less clear because of cultural ideas of representation. For example, “sun” was typically imagined as having curved rays radiating from it, in a swastika-like pattern, hence producing a “sun” glyph very different from an English-speakers idea of what “sun” should look like, perhaps with spiky “rays.” Stars were little crosses (or asterisks).
Some glyphs are more abstract - not really representational, but iconic - but still in a sense show what they mean. For example. thôy ‘be located.’ It shows a circle (object) on a horizontal line (some surface), with a pointer under the line, marking the location of the object.
Then there are some glyphs that as yet have no “etymology.” They are used phonetically or for spelling abstract words. Although it is presumed they were originally representations of some object or other, the connection has been obscured by the millennia, and we still don’t know what they might have represented. Possibly, they represented words in the Milim language which no longer exist in Yuk Tepat.
