Edges are first offset a specified distance away from and parallel to their original (i.e. starting) edge positions. These offset edges are then extended to points where they intersect with adjacent edge offsets. However a limit must be imposed on how far mitered vertices can be from their original positions to avoid very convex joins producing unreasonably long and narrow spikes). To avoid unsightly spikes, joins will be squared wherever distances between original vertices and their calculated offsets exceeds a specified value (expressed as a ratio relative to the offset distance).