Something doesn’t seem right. No symbols appear to span an edge of the stone as if it was part of something larger.
The spiral at the ‘bottom’ indicates that the writer was from a different Galaxy and the circle with a dot in the center indicates that their home planet is the only one around their Sun.
The three sloped lines says there were originally three ships but two of them crashed or were lost.
The writer was the only survivor of the expedition and all he had was a knife to hunt and kill animals for food...........
Good observation. I didn’t catch that. It does seem a bit lucky.