public BodyConstructor WithShape(Shape shape)
{
if (fixtureBuilderData.Count > 0 && Shapes.Count > 0)
throw new BodyConstructorException(
"Ambiguous Body definition; multiple unnamed shapes and multiple " +
"named fixtures supplied. Either have a single, unnamed default shape, " +
"or supply each named fixture with a specific shape.");
Shapes.Add(shape);
return this;
}