[jcassee]

So if this is what remained on the cave wall ... it was the plan that killed the whole tribe?

[pletnes]

Or maybe they didn’t have whiteboard markers, only permanent ones.

[kalonis]

They had both, but some new hire confused them.

[failrate]

If someone writes on a whiteboard with a permanent marker, immediately black it out with a dry erase marker. Then wipe it off. The dry erase marker's solvent will release the permanent marker ink.