in reply to
Re^2: concatenating identical sequences
in thread concatenating identical sequences
However, the merge is not so clean and results after the merge seem not to be in equal chunks (I have posted this on to my scratchpad).
I missed this bit of your spec: "(except for the very last chunk at the end of each block which might be shorter than 10 letters)".
Looks like you'll have to use Limbic~Region's solution of splitting the lines and storing the data as arrays.
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