An Irish poetic form, the Dechnad Cummaisc uses quatrains with both end and internal rhymes. The guidelines are as follows:

Each stanza consists of four lines
Lines 1 and 3 are 8 syllables each
Lines 2 and 4 contain 4 syllables each and end rhyme with each other.
The last word of line 3 rhymes with the middle word of line 4.
There is no limit to the number of quatrains used

Example

Cacophony of Discord by JezzieG

The night assaults all the senses
Crashing sublime
As beauty and terror collide
Waves ride and climb

Horror of tempestuous sea
Foreboding night
Elements dictating our fate
A date with fright

Sweeping clouds into the darkness
Of breaking ships
Of defeated broken remains
Wind strains and whips

The beams of light let them all down
Frantic scrambles
In the lost echoes of discord
Towards shambles

Towards boulders along the shore
Lightning strikes shocks
Storm’s aftermath revealed at dawn
Death on the rocks