Shakespeare’s Iambic Pentameter

The mathematics of Shakespeare's poetry revealed through the example of his Sonnet 18:

SONNET 18

Shall I compare thee to a summer's day? 
Thou art more lovely and more temperate:

Rough winds do shake the darling buds of May,

And summer's lease hath all too short a date: 

Sometime too hot the eye of heaven shines,

And often is his gold complexion dimm'd; 

And every fair from fair sometime declines,

By chance or nature's changing course untrimm'd;

But thy eternal summer shall not fade

Nor lose possession of that fair thou owest;

Nor shall Death brag thou wander'st in his shade,

When in eternal lines to time thou growest: 

So long as men can breathe or eyes can see,

So long lives this and this gives life to thee.