this article has caused a lot of discussion and dissent. The main text is withdrawn. The link to the SCCA flag manual is still here.
The actual SCCA Flag Manual
It may be found here (it's hard to find on the SCCA website). This is the 2012 manual, but as of this writing (late 2020) it's still current.
http://www.averillpark.net/SCCA/F_C%20Manual_revised11.11.2012_ApprovedCRB.pdf