Puzzle Description:

Dr. Jonas Salk, creator of the polio vaccine, introduced in 1955. From 1954 to 1962, U.S. polio cases dropped from 37,476 to 910. Results might have been even better, but vaccine distribution had some serious snags.

#1: Robyn Broyles (ginkgo100) on Aug 6, 2009 [SPOILER]

You can find more information here: http://tinyurl.com/nmyloz Dr. Salk also refused to patent the vaccine so that patent issues would not affect distribution.

This is my first PBN portrait.

I worked hard to get this line-logic solvable (no edge logic for once!). There is one exception at the very end. In my test-solve, I had to resort to what Jan calls two-way logic (I have always called it if-then logic, but that's no improvement). If you're stuck, here are the details:

If R38C23 is black, then C22 and C24 in that row are white.
In the row above, R37, either C22 or C24 must be black, but neither can be black because both C22 and C24 would need to be part of a block of 2. Therefore, R38C23 must be white. From there, you can finish with ordinary line logic.

Great job! I didn't know what he looked like, so I had to look him up, and you did him wonders.

Teresa will probably read my mind yet again and post a link to the picture I used as a model!

Thanks for a delightful puzzle. Keep up the good work.

Wonderful puzzle!

Robyn, this is a fantastic image. I don't think I even need to look at the photo, because the image is so clear. It did take me forever to solve, but it was worth all the pixel hunting. :-)

I didn't know about the refusal to patent. Very interesting.

Found to be logically solvable by Gator.

I did something similar to what you did in that area. I thought about it like this:

I had one 2 clue to place in column 24. It could go in one of two places. In either place it went, it would make R39C23 a dot.

By the way, in your explanation it should say R39C23, not R38C23.

Great image.

great image and solve

Very good image. Interesting solve.

hopefully his successors are on the brink of finding a way to end this current plague ...

nice image. logically solved.

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