Hey Roscoe, Welcome to the Board!
I'm guessing you are wondering about the black coloring on your rock.
The focus could be a little better on your pics, but from what I can tell
it looks like natural mineralization in the rock to me.
Actually looks like a layer of the black on top of the white. So if it is a "drawing" it would be more like an "etching" where the black layer has been scratched or "pecked" away.
But I'll go with whatever you decide.
Thanks for the pic and question.
Joe

Those are better pics, Rosco, thanks.
I can see now that the greyish, darker layer on the surface is definitely a concentrated coating
of a mineral like quartz, calcite, or something. Seeing that type of thin layer on the surface of rocks
is very common because that's a weak spot where the rock can break easily.
But I'm sorry to say there is no possible way for me to say if the
design has been "etched" or ground into the stone from looking at a picture.
And even if you can determine that the markings have been etched or ground into the stones surface
you still have a ways to go to say it was done intentionally by man.
So it goes.......
Now if you could find somemore pieces that all fit together......