The electronic spreadsheet, see both as a model of the classical chalkboard spreadsheet and as a paradigm (if a rather peculiar one) for certain kinds of programming. A key feature of the SpreadsheetModel is the use of ConstraintModels to bind the values of cells to each other, allowing instant update for both data recording and speculative analysis. 

The SpreadsheetModel is one of the few truly innovative ideas to arise after the end of the ElderDays.

''chalkboard spreadsheet''? Surely it's a model of the financial/accountant's paper spreadsheet, widely used before computers (and still used now). See http://en.wikipedia.org/wiki/Spreadsheet
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See Also: CollectionOrientedProgramming, TableOrientedProgramming
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ProgrammingParadigm