Normal (geometry) Normal (geometry) In geometry, a normal is an object such as a line or vector that is perpendicular to a given object. For example, in two dimensions, the normal line to a curve at a given point is the line perpendicular to the tangent line to the curve at the point. In three dimensions, a surface normal, or simply normal, to a surface at a point "P" is a vector that is perpendicular to the tangent plane to that surface at "P". The word "normal" is also used as an adjective: a line normal to a plane, the normal component
All that glitters is not gold wrote "Do not hold everything gold that shines like gold" in 1175. Chaucer gave two early versions in English: ""But al thyng which that shyneth as the gold / Nis nat gold, as that I have herd it told"" in "The Canon's Yeoman's Tale", and ""Hyt is not al golde that glareth"" in "The House of Fame". The popular form of the expression is a derivative of a line in William Shakespeare's play "The Merchant of Venice", which employs the word "glisters," a 17th-century synonym for "glitters." The line comes from a secondary plot of the play, the puzzle of