The felting was unintentional, but not a bad effect. The yarn used was Naturespun and Brown Sheep worsted, bought in 1991 in Lexington, KY. I bought one skein of several colors, and then was confronted with the question of what to do with these small quantities (I had bought 3 skeins of teal, luckily, which became the unifying theme.) I knit the sweater the following year, while watching the Olympics up in Vermont, (and more - it took nine months total.) Entrelac is a painstaking process, because it involves row turning on each square. It felt like making a mosaic out of eggshells, but the effect is (almost) worth the effort. There is a grafted decrease in the sleeves which enables the size of the squares remain constant while the sleeve tapers.