Thirty-six tiles cover 71.5 inches square once locked together, enough floor for a toddler to crawl, tumble and build on. Each 12.5 by 12.5 inch square is 0.4 inches of EVA foam with a removable letter or number at the center, covering A to Z and 0 to 9, so the same mat teaches counting and letter recognition while it protects knees. Pulled apart, the empty frames stack into cubes, tunnels and boxes, which turns a floor covering into a construction set. The surface is waterproof and wipes clean, and the anti-slip texture holds position on laminate or tile. Total weight is 5.5 pounds for the full set. It suits children from ten months up, and tiles can be added or left out to fit a nursery corner rather than a whole room.