Hierarchical Task Analysis
Below is a hierarchical task analysis for using Second Life–based turtle graphics in the scenario above. It is relatively general though, and could accommodate focusing on the geometry applications rather than on programming. Many of the tasks to be completed relate to preparation for using Second Life in general (rather than the turtle graphics system in particular); since we cannot change how these are implemented, they have minimal impact on our design. The most interesting aspect of the HTA for the design is the distinction between interactively commanding the turtle, and using a cycle of editing a script, saving it, and having the turtle run it (see task 2.3.2.2.2.2 and subtasks). As the scenario has already suggested, these both make sense in different circumstances, and cannot easily both fit into the same interface (or not the same part of it).
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