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I noticed that it let me in too much too, so I got rid of it. Even with multiple shapes.

Its problem is it just measures what pixels you color in, and not the sequence you color them in.
 
I have this app and love it. He released an update today that changes the sensitivity of the shapes drawn. It is quite effective at locking out. The only way I feel he could improve it would be to hide the swipes as they are drawn, so others can't see over the shoulder. But at high sensitivity, you have to be dead on, so it really is a good app. I recommend the most recent updated version.
 
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