Thomas LavergneHow come those rocks are so neatly sliced? Any rock expert here has a guess?
I saw them (and many more) in a dry river bed in the hills, northern #Italy.
Bob-o McNabb@lavergnetho someone practicing making Hasselback potatoes.
Mathijs Booden@lavergnetho My guess would be frost wedging exploiting pre-existing cleavage.
ScottinSoCal ๐บ๐ฆ ๐ ๐ณโ๐They're sedimentary rocks - laid down in layers by accumulated silt, then hardened to rock.
๐dam ๐ฎcheinberg // sethadam1
Zeolith 
Gelifraction? Water gets in, freezes, expands, fractures.
It's Italy so dunno if freezing happens often there.
berndandeweg@lavergnetho they have this in Iceland a lot. They call it Trolls Bread. It is due to moisture and temperature differences (on Iceland: bottom in the soil, top out in the cold air). Pre existing weaknesses help a lot to create nice bread loafs. Otherwise they crumble.
Simon Brooke@lavergnetho they're highly stratified rocks (likely shales and mudstones) which shatter easily on the discontinuities between the strata.
Imagine a river bed that dries out intermittently. While there's water, sediment gradually accumulates and packs itself neatly and densely, under gravity and lubrication. When it dries, the surface gets dusty, and when the next inundation comes the next layer of sediment doesn't adhere so well to the previous one.
@simon_brooke sounds plausible, thanks.