I remember reading about Flexigons in SciAm while in Jr. High School. And colored the faces, concealed messages, etc. The mma.org link is interesting as Bryant Tuckerman, Richard Feynman, and John Tukey are mentioned on page 3 as some who worked with flexigons.
Or you could watch this :
This video is based on, and in honor of, Martin Gardner's first Mathematical Games column from 1956, "Hexaflexagons," which can be found here: http://maa.org/pubs/focus/Gardner_Hexaflexagons12_1956.pdf
Blog Make a Frequency Plan Tom Burke 17 comments When designing a printed circuit board, you should develop a frequency plan, something that can be easily overlooked. A frequency plan should be one of your first steps ...