http://www.redmonk.com/jgovernor/2008/10/17/on-timeless-software-pace-layering-and-the-sap-software-architecture/
-- perl -ple 's:20(\d\d)([01]\d)([0123]\d):qw/fri sat sun mon tue wed thu/[($1*1.25+$3+(1,4,4,0,2,5,0,3,6,1,4,6)[$2-1])%7]:e'
http://www.redmonk.com/jgovernor/2008/10/17/on-timeless-software-pace-layering-and-the-sap-software-architecture/
-- perl -ple 's:20(\d\d)([01]\d)([0123]\d):qw/fri sat sun mon tue wed thu/[($1*1.25+$3+(1,4,4,0,2,5,0,3,6,1,4,6)[$2-1])%7]:e'