One embodiment a vision substitution system for communicating audio and tactile representations of features within visual representations includes selecting (1) activity-related parameters; obtaining (2) images or other visual representations according to the activity-related parameters; acquiring (3) features including shapes and corners related to the visual representations according to the activity-related parameters; and outputting (4) effects related to the features on audio and/or tactile displays according to the activity-related parameters. The corners of shapes and other lineal features are emphasized via special audio and tactile effects while apparently-moving effects trace out perimeters and/or shapes. Coded impulse effects communicate categorical visual information. Special speech and braille codes can communicate encoded categorical properties and the arrangements of properties.