The trick works perfectly if you have an iPhone, however the few times I've presented this I've
gotten more of a "Hm, I didn't know you could do that" or "how much did that app cost" response,
instead of, "wow that's magic!" Maybe it's just me but I find a trick based in pure technology has a
hard time presenting itself as magic. The effect still does what it says and if you can be creative
and work in more phone tricks it is definitely a cool little piece to add, especially for free.