I Don't know
Hi - maybe this is all easier than you think.
Just remember which squares (cells) you chose, and read off the numbers which appear in them. Easy-peasy in our humble view.
Also GrIDsure NEVER works on 'touch screens' so you won't need to trace your pattern/shape with your finger (which could give information to a shoulder surfer).
Once you've actually seen how it works, we think you'll see how simple, secure and anxiety reducing it is (www.gridsure.com/slideshow - OR try the actual demo on the site for yourself).