Blocking acrylic yarn

[GrumpyGramma]

I just came across this site and thought I'd share with anyone who might be interested. I've not tried it. http://a-modicum-of-ingenuity.blogsp...ylic-yarn.html I've seen reference to using those kid's interlocking blocks, kind of like puzzle mats, for blocking and think they could be used in place of the foam core board mentioned.

Keep in mind that your blocking will be permanent.

That's from the site. I don't understand why it's permanent, it seems to me that once washed and thrown in the dryer it's going to do its own thing again. What am I missing?