Lee Berger's announcement video on the find - it's long-ish, but it's very very interesting if you're into this stuff. https://youtu.be/fFbgQhY4Yxw Something very evocative is the resemblance to Neanderthal cave engravings (@16:45 in the video) - that same theme of cross hatching, with multiple length verticals. As Lee points out, ascribing meaning to these things is going to be pretty much impossible, but it's very…
Obviously this is pure imagination but I wonder if that was why they felt the need to scratch the rock or create lines to block it from spreading.