What are the two types of circle or spiral search pattern?

• A. Expanding circle and contracting circle
• B. Narrowing circle and widening circle
• C. Circular pattern used interchangeably with grid
• D. Tight circle and loose circle

Answer: (B)

Circle or spiral search patterns organize coverage by how the search radius changes with each pass. The two forms are narrowing circle and widening circle. In a narrowing circle, you start with a broader sweep near the outer area and move inward, shrinking the radius as you continue. In a widening circle, you begin at a central point and expand outward, increasing the radius with each pass. This approach ensures systematic coverage and helps prevent gaps as you move through the space. While other phrasings like expanding/contracting describe the same idea, the common terms used here emphasize switching from larger to smaller radii or vice versa.