This study was concerned with the effects of stimulus dimension (two vs. three dimensions), mode of exploration (visual or haptic), and the combination of these two variables on preschool children's responses to pattern meanings and unusual uses tasks of original thinking. Eighty children (aged 4 years 10 months to 5 years 5 months) were randomly assigned to four task conditions. To determine the construct validity of each type of stimulus presentation, four criteria were identified and examined. The findings indicated that in measuring original thinking, in terms of ideational fluency, presentation of tasks in 3-D yields higher scores than in 2-D form and that permitting visual and haptic exploration does afford higher scores than does use of visual only. That is, the 3-D in comparison with 2-D tasks generated more responses overall and more unique high quality responses in particular. Furthermore, the combination of 3-D with visual and haptic exploration is the only condition studied to meet all criteria for construct validity as specified in this study. The occurrence of increased fluency and the relationship between fluency and high quality original responses are discussed in relation to Mednick's (1962) response hierarchy and to the creativity-intelligence distinction (Wallach, 1970, 1971).