Tartaric Acid

an organic acid which exists in four forms that are STEREOISOMERS. The commonest form (d-tartaric acid) is used in dyeing, the manufacture of baking powder and "health salts". Another form (dl-tartaric acid, or racemic acid) occurs in grapes

Taken from Dictionary of Science

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Tartaric acid is a white crystalline diprotic organic acid. It occurs naturally in many plants, particularly grapes, bananas, and tamarinds, and is one of the main acids found in wine. It is added to other foods to give a sour taste, and is used as an antioxidant. Salts of tartaric acid are known as tartrates. It is a dihydroxy derivative of succinic acid.

Tartaric acid was first isolated from potassium tartrate, known to the ancients as tartar, c. 800 by the Persian alchemist Jabir ibn Hayyan, who was also responsible for numerous other basic chemical processes still in use today. The modern process was developed in 1769 by the Swedish chemist Carl Wilhelm Scheele. The chirality of tartaric acid was discovered in 1832 by Jean Baptiste Biot, who observed its ability to rotate polarized light. Louis Pasteur continued this research in 1847 by investigating the shapes of ammonium sodium tartrate crystals, which he found to be asymmetric. Pasteur was the first to produce a pure sample of levotartaric acid.

Taken from Wikipedia

Quadrilateral

any geometric shape that has four sides, e.g., a rectangle, square, kite, parallelogram, rhombus.

Taken from Dictionary of Science

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In geometry, a quadrilateral is a polygon with four 'sides' or edges and four vertices or corners. Sometimes, the term quadrangle is used, for analogy with triangle, and sometimes tetragon for consistency with pentagon (5-sided), hexagon (6-sided) and so on. The word quadrilateral is made of the words quad and lateral. Quad means four and lateral means sides. The interior angles of a quadrilateral add up to 360 degrees of arc.

Quadrilaterals are simple (not self-intersecting) or complex (self-intersecting). Simple quadrilaterals are either convex or concave.

All convex quadrilaterals tile the plane by repeated rotation around the midpoints of their edges.

Taken from Wikipedia