ocr: 44,2- Tet's follow che progress, as lime marches un, of E Puincere section of the thick surtacc. This appeara ro he a Ine-sesmenl al lirst. As we shull soon scc, it 15 accually a ttick the-segment. lirst it extends backwards away from us, curving tO the left and around a circle. Al the same time, it widens End falds DVCL. Eventually it reaches double its original width, foluing all the way erver, and comes back tO the Poincare seclion as a U-shaped chaanel.