what are the strange checks or grooves that are cut into the granite that lies at sides of the pyramid in cair

Answer 1

Which pyramid at Cairo are you referring to? Where abouts on the pyramid?

Are you referring to the hieroglyphs? Hieroglyphs adorn most ancient buildings and tombs (Valley of the Kings, Karnak, Abu Simbel, etc.).

Answer 2

They could be Heiroglyphics as previously answered which are the way the ancient Egyptians wrote down important events, with names inside rings which are called (excuse spelling mistakes) "kartouches". The writing does not use syilables as most modern languages do they represent things such as people or gods or other items in a similar way to traditional Chinese does although they are unrelated.
Otherwise they could be the marks left from the tools used to carve the granite from the quarries such as are left behind on many unpolished rock surfaces, these look like striations a geological term for "scarring" left on rock surfaces as 2 they rub together during a period of faulting. The difference is that the carving marks are much more irregular as different people with different strokes carve in different places on different days, also the same person won't always hit the same spot every time and so the line of cutting left behind becomes uneven.