Pictograms scrawled on walls by homeless wanderers and migrant workers for the benefit (and wellbeing) of fellow travellers during the Great Depression in the US.
From a series of eight 50cm x 70cm posters by Swedish design artist Viktor Hertz
See (and/or buy) the full set here.
Movie posters reinvented as pictograms by Viktor Hertz.
More at Viktor’s Flickr photostream.
He also sells them here.