A Haiku is composed of a 5-7-5 structure. This means that it has three lines in which case the first and last have five syllables and the middle line has seven syllables. 3-5-3 is only a shortening of that. here are some examples:

God made man,
man was good and small,
man made god.

Sun on shirt,
lamp light in my hair,
cold fingers.

Cat ate lamb,
lamb bled with sad joy,
same person.

Red pine trees,
from the setting sun,
and red rock.

Rain all week,
nightmare about hell,
Sunny day.

value in itself,
no one saw.

White black fog,
neon yellow tree,
fall wet dark.

Red white sun,
if men could chain it,
what horror.

Cigar smoke,
apartment complex,
talk downstairs.

The same place,
food, stink fog, fire, flame,
birth and wood.

Empty sky,
makes the field boring,
but alive.

Christian love,
is not approval,
it is love.

We borrow,
not money or goods,
our selves.

heavy cloud,
floating purple rock,
the weightless