S: (n) stratification (the placing of seeds in damp sand or sawdust or peat moss in order to preserve them or promote germination)
S: (n) juxtaposition, apposition, collocation (the act of positioning close together (or side by side)) "it is the result of the juxtaposition of contrasting colors"
S: (n) tessellation (the careful juxtaposition of shapes in a pattern) "a tessellation of hexagons"