Reflective of man’s influence on nature, formal gardens are often characterized by well-defined structure and geometry. Organized around a central axis or pathway, formal garden designs focus on symmetry and easily recognizable ground patterns. Often, this axis features a sculpture or decorative ornament for effect and a focal point. The materials' palette is generally kept to a minimum, with gravel and regular paving stones. The main planting features consist of lawns and hedges, the latter being used to define space, edge borders, or create parterres. Adding height, pleached trees may be introduced to create ordered avenues while decorative borders may be planted to soften the garden’s rigorous geometry.