Large-sample item response data for the 10-item Paper Folding worksample 622 (N=2,749) and for five new experimental paper folding items (N=2,514) are analyzed with the logistic item response model and with full-information item factor analysis. The main results of the unidimensional analysis are that: (1) item discrimination is heterogeneous, so that a Rasch model cannot be ascertained for the Paper Folding worksample; (2) item difficulty does not increase with presentation order; and (3) there are not enough items in the midrange of the scale. Item factor analysis identifies an additional minor factor attributable to during-the-test learning of specific solutions for items with similar stems. Based on these results, a modified 11-item version of the Paper Folding worksample is proposed. (Six graphs and five tables present the data.) (Author)