About this poem:

Definition of Senryu

1) A Japanese poem similar in structure to haiku, but more concerned with human nature, and is often humorous or satiric -- usually in three lines of seventeen kana.

2) A foreign adaptation of 1, usually written in three lines of 17 syllables or LESS.

Again, unless you are Japanese, have been writing Japanese, or speak fluent Japanese, you will be writing definition #2.

A good structure for beginning senryu poets is:

setting
subject and action (on two lines)