There is no such thing as a dead thread. Yes, sometimes links can get broken during server moves, but they are usually able to be recovered.  I've updated the links in the above threads.

Here is a dynamic mattress

 

Here is a morphable sheet

"It is good to see ourselves as others see us. Try as we may, we are never
able to know ourselves fully as we are, especially the evil side of us.
This we can do only if we are not angry with our critics but will take in good
heart whatever they might have to say." - Ghandi