| | The Symmetry454 Calendar (Site not responding. Last check: 2007-10-14) |
 | | The Symmetry454 Calendar is a perpetual solar calendar that conserves the traditional 7-day week, has symmetrical equal quarters, and starts every month on Monday. |
 | | This document, entitled All about the Symmetry454 Calendar Leap Week, introduces various leap rules that could be used with the Symmetry454 Calendar — most could just as easily be adapted to almost any other calendar. |
 | | This document includes the full "soup mix" of new leap rules: the Rotation-Adjusted Year (RAY), Revised Julian variant of the ISO standard leap rule (RJiso), mean and actual astronomical leap rules, and fixed arithmetic leap cycles for the Northward Equinox or North Solstice. |
| individual.utoronto.ca /kalendis/symmetry.htm (998 words) |