(hint #1) Being able to play whatever I want has been a central theme to my own discovering how to play guitar. I've been on that path for 37 years, and it's enabled me to uncover, test and refine a unique, skill generating learning approach.
It is important to note that urethane foam is most commonly used to refer to a material made from polyurethane. The urethane reference in this name is to the type of links, also known as carbamates, that join the units in polyurethane.
The Differences Between Urethane and Polyurethane. Each day we use several products made of organic compounds that influence our lifestyles. Urethane and polyurethane are the first among them. Many think the only difference between the two is that polyurethane is produced by linking urethane organic units. As you see in the picture below, far more dissimilarities exist even though the names are sometimes substituted for one another.