_ | | | | -
Second box:(10 with a line)
_ _ | | | | | | - -
Third box:(14 and 2 lines)
_ _ _ | | | | | | | | - - -
Now all these are nothing more than guesses on my part. Post again to algebra.com with specific diagrams. Or you could write to me at this email: xcentaur-AT-hotmail-DOT-com (symbols removed to prevent spam harvesting).
Also,what do you mean 'letters'? I understand m for matches...what do you mean 'letters' in your question? Do you mean the boxes...?
Only once I know how the figures look can I try to help you.
Until then,keep trying and good luck.