This study used a balanced factorial design to examine the performance of normal young adults on a parquetry block assembly task that occupational therapists use to treat constructional deficits in adults. Ninety-six 18- to 34-year-old right-handed college students or college graduates (48 men and 48 women) were tested. Independent variables were subjects’ sex, presence or absence of color on the model design card, and amount of detail on the model design card. Dependent variables were speed and accuracy of design construction. Results of a factorial analysis of variance with the three variables showed that the subjects’ total time scores were significantly related to their sex and to the presence or absence of color and the amount of detail on the design card. Interaction effects were significant for sex by amount of detail and for color by amount of detail. The results were used to generate clinical performance criteria and graded levels of difficulty for this modality. The subjects’ learning and test behaviors were examined to generate ideas for treatment and for future research.