Five science teachers were observed during two selfstudy sessions where they learned to use Visual AgenTalk (VAT). In the first session they learned basic skills; in the second, techniques for reusing example simulations. Two reusable examples were developed, one a concrete example world, the second an abstract world. Although all teachers succeeded in learning VAT basics, we observed differences in reuse. It appears that the simplified components of the abstract world supported reuse to a

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... er degree than those of the concrete example world.