The Medicine Wheel and the Meridian of Time

The four parts of the wheel indicate the passing of time: birth, youth, adulthood, death. I've recently learned that the four corners of the earth in scripture also indicate markers of time, and not simply geographical directions. Within the earth's yearly journey around the sun are also four equidistant points (or corners) of significance: the equinoxes and solstices, each one marking the change of seasons.