Holmsburgers ,

I found similarity between 2D Perlin code and your brothers code. I think he got the function from your letter and he applied to his code. If he has the written code , it wouldnt be harder to produce the screen.
Holmes , I think You are very near to your final goal.
Ask him to visit the APUG and see the autochrome book cover scan. May be he could calibrate his code.

Best ,