(Make sure to read all posts on Birkat HaChamah here)In order to visualize the math behind Birkat HaChamah, please see these two charts.
- The Jewish Week - During a year that has Birkat HaChamah, Tekufat Nissan falls in hour 73 of the week, and advances 30 hours later in the week every following year. See this chart to see the make up of the week and the division in to hours. There are two sheets here to help visualize.
- Birkat HaChamah Cycle - After you have seen how the week is set up, this chart shows the resulting hour occurances of Tekufat Nissan in a 28 year cycle. I've put in color-coding to indicate the 4 year cycles mentioned in Rashi and Pirkei D'Rebbi Eliezer as well as the 7 year cycle.
Comments are welcome.