Abstract: This paper argues that grid-based spatial reasoning can significantly improve human-computer interaction. While grids constrain the user’s ability to position objects on a screen on one hand, they greatly increase the transparency of functional relationships among these objects on the other hand. A system called Agentsheets employes the notion of agents organized in a grid. The spatial relationships between agents are used to capture design properties independent of domain and programming language. Two types of spatial relations are distinguished called strict-spatial relations and pseudo-spatial relations. This paper gives a short introduction to Agentsheets, explains how Agentsheets address problems of construction kits, sketches sample applications, and evaluates the contribution of grid-based spatial reasoning to human-computer interaction.

Abstract: Panel: • Chauvet Jean-Marie: portablity, cross platform development • Bruce Tognazzini: many of the current user interface designgs are still based on the very limited first Macintosh implementation. Therefore, they propagate many desing decisions that were valid then but unjustified today David C. Smith: proactive versus reactive user interfaces, agents to access information, human-human communication, end-user programming, we are still at the level of the Star