"I'd forgotten that story.

I am sure it will help." He walked away, leaving her poring over the picture, but presently, as he paced the deck, he felt her light touch on his arm, and turned to see her glowing little face looking up into his.
"I've got it!" she cried.

"The picture made me think of the very thing.

I had been fumbling with a tangled skein, trying to find a place to begin unwinding.

Now you have given me the starting thread, and it all begins to smooth out beautifully.