found, out and about [found drawings]

witnessed in the course of a walk through town yesterday, some freshly discovered or found drawings... please allow me to explain...the object in question (the receptacle for the accidental, found drawing, the surface, the substrate) is a metal seat or bench, probably made of alluminium, covered in a powdery black mould, which made it rather undesirable or unsuitable to sit on, especially if wearing light-coloured summer attire...here, in the first snapshot, one can see the pre-formed grooves in the metal seat, which serve to make the metal bench less slippery to sit on but they also echo the wooden slats of a traditional bench, which are further emphasised by the dark, weathered patina of black mould, here containing the accidental drawing as a series of negative mark-makings between the two sets of parallel lines...in this second example, the accidental dints and scratches in the metal have been subsequently colonised by the black mouldy mildew, forming a positive mark or trace...and here, in the final image taken, is a more formal composition, zoomed in to accentuate the visual contrast between the parallel grooves and the more free-form, expressive scratches or incisions below... i almost see a signature in the lower right...now, my only quandary here is, are these just more found drawings or an example of some creative, found printmaking(s), given that the grooves, the engraved marks, the incised traces, those made unintentionally, are later inked in by nature, and the myriad tones of accumulated mould or mildew (seen most clearly in the first image) are reminiscent of a coarse, hand-applied aquatint...in fact, had i not explained that these are just photographs, one might reasonably conjecture that they are the result of a process of intaglio printmaking, an etching or drypoint engraving...lastly, the bench also exhibited the usual marks of graffiti, some lewd symbols, words, names and numbers... but these were not so interesting in this context...