These macromolecules are polar [polar: having different ends] because they are formed by head to tail condensation of polar monomers. Let's look at the three major classes of macromolecules to see how this works, and let's begin with carbohydrates.
Bostwick Steel Lath Company advertisement for steel truss loop type metal lath in 1920. A lath or slat is a thin, narrow strip of straight-grained wood used under roof shingles or tiles, on lath and plaster walls and ceilings to hold plaster, and in lattice and trellis work.
Lath screws are perfect all-purpose fasteners. The modified truss head provides an extra bearing surface. They are commonly used for projects where a low profile is required. Phillips II Plus Lath Screws are coated with a clear zinc coating that is rust resistant but not rust proof for outdoor use.