A set of filter rules are applied to pieces of text. Information about regions of negative parallax within the entropy reduced image of an image pair is encoded along with the images. Each platform is provided with an abrasion-resistant exercise surface assembly configured to slidingly communicate with and to controllably engage and disengage a user’s footgear. Each panel includes a peripheral edge having a groove formed into the peripheral edge such that the groove is continuous and extends about the entire peripheral edge of the panel.