Using Complex Chains and Complex Shapes
A complex chain (sometimes called a "complex string") is a series of connected open elements (lines, line strings, arcs, curves) grouped for manipulation as a single entity.
A complex shape, like a complex chain, is a series of connected open elements grouped for manipulation as a single object. The difference is that the first and last element in a complex shape are connected, thereby closing a shape.
Left: Complex shape created from arc and line string with Create Complex Shape tool. Center and right: Union and intersection of circle and block created with Create Region tool.
You can create complex chains and shapes, from existing elements, with the Groups tools. Also, you can use the Place SmartLine tool to create a complex shape or chain.