Is it possible to discern the exact line in deep fog that divides seeing and not seeing? Can you stand in one place, blinded by fog, then pivot in place and suddenly see the invisible?

Wood chairs, disassembled into slatted signage, onto which a poem is etched, one line per slat, in a process that renders the words invisible unless the wood is wet. Installed at a coastal viewpoint where the public goes to watch for gray whales which have been migrating past for hundreds of years. When it's sunny, no one looks at the poems -- there is nothing to see, anyway. When fog obscures the whales and amplifies the waves, leaving no evidence of place except sound and your own wet breath, the poem appears.