ABC RN Life Matters had a great talk by Daniel Kish this morning on blind people using echo-location to ‘see’. He can train them to use it in 2-3 days.
http://www.abc.net.au/radionational/programs/lifematters/daniel-kish/3842912
The technique involves making little click-clicking noises and listening to them returning.
A technique that does not rely on non-locally produced materials just our own trainable abilities!