 Maurice's reforms are more famous for the effect they had on others—taken up and perfected, and would be put to the test on the battlefields of the seventeenth century.After bad experiences with the classic tercios formations in Poland, Gustav II Adolf decided to reorganize his battlefield formations, initially adopting the "Dutch formations", but then adding a number of innovations of his own.He started by re-arranging the formations to be thinner, typically only four to six ranks deep, spreading them out horizontally into rectangles instead of squares.