#paving_stone  a stone used for paving
  supertype:  stone  building material consisting of a piece of rock hewn in a definite shape for a special purpose; "he wanted a special stone to mark the site"
  substance of:  pavement
  subtype:  cobble__cobblestone__sett  rectangular paving stone with curved top; once used to make roads
  subtype:  curbstone__kerbstone  a paving stone forming part of a curb
  subtype:  flagstone__flag  stratified stone that splits into pieces suitable as paving stones

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