Touchscreens are Fingerpaint

This post analyzes how touchscreens fundamentally alter traditional GUI design paradigms by breaking the abstract pointer model and impacting Fitts's Law. It introduces the concept of 'fingerpaint' interaction, emphasizing the need for larger touch targets due to finger size, the problem of hand occlusion, and the influence of eye focus. The post also discusses the implications of virtual edges not stopping real fingers, the role of handedness and fatigue, and the potential of multi-touch gestures. It concludes by highlighting the increased intimacy and responsibility programmers have with users due to direct physical interaction.