Semi-Formal is almost formal
The most important aspect to consider when designing a formal pond is the shape, or outline. Formal ponds are always symmetrical, meaning that one side is a reflection of the other. Typically, straight or precisely arched lines are employed to create the outline of a formal pond. Common shapes for a formal pond include square, rectangular, circular and hexagonal. Some ponds have an outline made up of a combination of these shapes that creates an ornate, but symmetrical design.