Article Grading: The following comments were left by the quality and importance raters: (edit · history · refresh · how to use this template)
Geometry guy 15:12, 10 June 2007 (UTC)
The red arrows in the figures on this page are misleading. As vectors, the arrows should be on the opposite end. -- JackSnoeyink 04:00, 18 April 2007 (UTC)