Oh, but the polygonal "analysis" overlayed on that circular splotch with the drip marks as an alien's "handwriting" example is corny beyond words. Correlating an arbitrary set of points on splashy drippy smears, and eureka! It's a symbol for the global landing sites across seven continents? Yeah right. That leap in counter-intuitive conceptualization is on the level of bat shark repellant, or Roland Emerich's super c…
To me, the intent in the movie was pretty obvious: specific polygonal clusters attached to the circle act something like radicals in kanji, but with even more components that can be built into a single 'word'. Your complaint strikes me like complaining that kanji calligraphy (for example: https://i.imgur.com/wHdqJIF.jpg ) obviously can't mean anything because it's just splashy ink marks.
A circle is an elegant way to encapsulate a lot of information in a compact symbol. These aliens could be really good at detecting angles. If their eyes have cones polarized at different angles, shapes placed at different points on the circle could appear to be written in different colors to them. That would be just as natural as words written in a line are to us. Fascinating stuff.