Since the NinjaFlex version of printed Braille has enough detail and so is easily readable by a user, we printed the entire overlay in pure NinjaFlex including Braille. As guided by the user who tested our second design above, we also improved our design of the embossed letter version to make the letters thinner with larger gaps between letters for distinction.

For this improved design, we further tested the legibility of the Braille labels with two blind individuals (one female), both of whom provided formative feedback on the design. One suggested making the Braille dots more distinctive by raising the dots higher or reducing the button height. The other Braille expert, who works for a Braille publisher, suggested that Braille dots with a convex top are easier to read by touch than with a flat cylindrical top because convex tops provide a more salient separation between adjacent dots. Therefore, we changed the Braille dots from cylinders to domes, and finalized our design for the user evaluation we present next.