Abstract: This paper describes how spatial and temporal metaphors can play an important role in making the task of programming serve problem-solving processes. Visual programming research hopes to capitalize on innate human perceptual skills to make the programming task easier by using visualization to simplify program construction at the syntactic level. Instead, we advocate that the role of visualizations, and the consequent use of spatial metaphors, is not to simplify programming per se but instead to support the problem-solving process. To that end, environments endorsing spatial metaphors should support: creating and changing external representations of the problem, and opportunistic design strategies necessary for exploring problem spaces. Furthermore, we discuss problems with human-computer interaction schemes arising from the use of temporal metaphors. Direct-manipulation, on the one hand, can be too direct for controlling a number of autonomous processes such as cooperating agents. The complete delegation of tasks to agents, on the other hand, can leave users entirely in the role of passive observers. We propose a new approach, called the participatory theater metaphor, which combines the advantages of human computer interaction schemes based on direction manipulation and delegation and provides users with a continuous spectrum of control over their program behaviors. Five principles for the design of computational systems, originating from the programming as problem solving perception and the participatory theater metaphor, are enumerated. These principles are embodied in the Agentsheets system. Agentsheets is a substrate for constructing domain-oriented, dynamic, visual problem-solving environments. These environments consist of cooperating agents organized in temporal and spatial metaphors. The five principles are illustrated with examples from applications built using the Agentsheets substrate.

Abstract: Many teachers yearn to break through the confines of traditional textbook-centered teaching to present activities that encourage students to explore and construct their own knowledge. But this requires developing innovative materials and curriculum tailored to local students. Teachers have neither the time nor the information to do much of this from scratch. The Internet provides a medium for sharing innovative educational resources globally. School districts and teacher organizations have already begun to post curriculum ideas on Internet servers. However, just storing unrelated educational materials on the Internet does not by itself solve the problem. It is too hard to find the right resources to meet specific needs. Teachers need productivity software for locating sites of materials across the network, searching the individual curriculum sources, adapting retrieved materials to their classrooms, organizing these resources in coherent lesson plans, and sharing their experiences across the Internet. We have designed and prototyped a Teacher's Curriculum Assistant (TCA) that provides software support for teachers to make effective use of educational resources posted to the Internet. TCA maintains information for finding educational resources distributed on the Internet. It provides query and browsing mechanisms for exploring what is available. Tools are included for tailoring retrieved resources, creating supplementary materials, and designing innovative curriculum. TCA encourages teachers to annotate and upload successfully used curriculum to Internet servers to share their ideas with other teachers. In this paper we motivate the need for such computer support and discuss what we have learned from designing TCA.