Geometric Art: Isolines or Contour Lines of Problem 1153, Triangle, Angle Bisectors, Perpendicular, Parallel Lines

Isoline
An isoline or contour line of a function of two variables is a curve along which the function has a constant value. Isolines usually have a parallel trend.

Parallel lines are lines in a plane which do not intersect or touch each other at any point.

See also:
Original problem 1153