I am afraid, I am stuck on the question 8 page 52 of the New edition (i.e. question 8 page 53 in the old edition).
This is the question with the 'strands of threads' or 'pen stroke' as you prefer...
I know that the answer needs 6 'strands' so answers c
has a very different pattern so is out too. (though my thinking is may be not rational enough or precise enough. May be you have a better explanation to cross this one out?)
But how can we chose between answer a
Thanks in advance for your help!