Wolfram Technology Guide: Automated Table Layout  previous | next 
Spanning Rows and Columns
Mathematica automatically handles arbitrary arrangements of spanning rows and columns.
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Click for copyable input
Grid[Table[

  RandomChoice[{SpanFromLeft, SpanFromAbove, 

    Item[RandomInteger[1000], 

     Background -> Hue[RandomReal[], .2, .9]]}], {30}, {15}], 

 Frame -> All]
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