11.   Photons are not matter in the conventional sense and do not have surfaces.

12.   The Swedish researchers, writing in the journal Nature, have described a new way of making a lens that has straight surfaces.

13.   They have uneven surfaces and are shaved at the corners so that the gold glows like a rainbow in the light.

14.   This is standard in any construction -- you must have reference surfaces to keep things square.

15.   Toys have flat surfaces to begin with, and no one ever saw a real dinosaur.

16.   Two other Scarpa pieces have surfaces like chipped wood.

17.   Those projects will be required to have porous surfaces, dry wells or use other techniques to allow rain water to enter the ground.