1 Stone countertops, including granite, other natural stone and quartz resin (engineered stone) cost $4-$150 per square foot, or $120-$4,500 for a typical 30 square foot kitchen countertop. 2  Stone tiles cost $4-$20 per square foot; slab stone countertops cost $50-$150 per square foot.
STL (STereoLithography) is a file format native to the stereolithography CAD software created by 3D Systems. STL has several after-the-fact backronyms such as Standard Triangle Language and Standard Tessellation Language.
Prior to STL 98 standardization, most of the STL header files had (.h) file extensions. It was decided to remove to .h extension at some point in time. I'm not sure why this was decided, but possibly to provide uniqueness For more info, see. conio.h is a Borland / MS specific header that contained console I/O functionality, and is not part of the standard. Including standard files with .h extension is (still) allowed by some compilers, but is considered deprecated.