Talky Bnonnsense #6: celebrating leap day by gathering the remainder

Why is the solar calendar not exactly 365 days? Why did God put a remainder of a day into every year, what does it teach us about the completion of time, and what does he want us to do with it? How can we better take hold of it, and exercise dominion over it, so that we are shaping the forms of our lives to reflect Christ’s rule?