Thirty Days Hath September (extended)

I just published an update to the poem Thirty Days Hath September. Here is a version that has verses to help keep track of Leap Years. These verses were easier to write because I was not constrained by the established poem:

Thirty days hath September,
April, June and November.

Seven months have one more day,
But February goes astray.

Three years, it hath weeks of four;
Leap Year, it hath one day more.

Most years that we add a day
Can be reckoned in this way:

Decades even: eight, four, aught;
Six and two for decades not.

Still, to synchronize our sphere,
Rarely, we must skip Leap Year.

Each year that can be divided
By one hundred gets decided.

If four hundred fails the same,
Then the leap it doth disclaim.

With this, everyone can become a perpetual calendar.