mbostock/topojson — pull request #83 by jasondavies (2013-06-20 14:50:53+00:00)
Title: Don't quantize each point more than once.

This can happen when processing TopoJSON input (type=Topology), where a
two-element array instance (point) may be reused more than once. This
was causing shared points to be quantized multiple times, resulting in
large and incorrect coordinates.