(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.
They were also used on WWII aircraft on a limited scale. Currently, urethane floors and urethane floor finish are one of the most historically used products in building and architectural planning. Because urethane floors are so flexible, they allow for high levels of foot traffic and large machinery usage.