Parallelogram? Geometry...it's what you say when you turn into a tree....Gee..I'm a tree...lol.
Between the white/black gums, the angles of the dangles of the anal fins...the chart I have now laminated from a few posts ago in my yak....If I screw my first posting up of a salmon calling it the wrong specie...
In Euclidean geometry, a parallelogram is a (non self-intersecting) quadrilateral with two pairs of parallel sides. The opposite or facing sides of a parallelogram are of equal length and the opposite angles of a parallelogram are of equal measure. The congruence of opposite sides and opposite angles is a direct consequence of the Euclidean Parallel Postulate and neither condition can be proven without appealing to the Euclidean Parallel Postulate or one of its equivalent formulations. The three-dimensional counterpart of a parallelogram is a parallelepiped. A quadrilateral with one pair of parallel sides is a trapezoid in American English or a trapezium in British English.