a circle A dartboard is typically circular, with concentric rings inside, divided into pizza like wedges that distinguish the different point areas.
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There is one outer ring and 4 inner rings.
On most dartboards it is six (6), but some dartboards have concentric circles.
Concentric rings in water are called ripples. Ripples are small waves that form on the surface of the water when it is disturbed.
The rings of an archery target are concentric circles.
Bone
topographic
Roads
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A Bullseye, culdesac, the store, Target's logo, a CD, tree rings, water ripples coming from a center point, and the rings of Saturn and Uranus, to name some.
a dartboard, 20