Relationship

A riddle for you
It's about this rope;
Well, may be steely wire for some
Others, fragile as spider thread
See the gradation of strength?

Binding like a chain,
Or loose like rubber string
Eros, Philia, Agape, Storge
See?

My own
is unusual
A bit of mix up
between those Love brothers
very tightly I hold to my end
the other end seems loose
See? - No you don't

Indeed,
A riddle for you and me
A riddle for humanity
...

And your answer?