The design and engineering of children's artifacts-like engineering in general-exhibits a recurring philosophical tension between what might be called an emphasis on "ease of use" on the one hand, and an emphasis on "user empowerment" on the other. This paper argues for a style of technological toy design that emphasizes construction, mastery, and personal expressiveness for children, and that consequently runs counter to the (arguably ascendant) tradition of toys that work "like magic". We describe a series of working prototypes from our laboratories-examples that illustrate new technologies in the service of children's construction and we use these examples to ground a wider-ranging discussion of toy design and potential future work.