A monotetra was developed by Michael Walker. Here are the basic rules:

Comprised of quatrains (four-line stanzas) in tetrameter (four metrical feet) for a total of 8 syllables per line.

Each quatrain consists of mono-rhymed lines (so each line in the first stanza has the same type of rhyme, as does each line in the second stanza, etc.)

The final line of each stanza repeats the same four syllables.

This poem can be as short as one quatrain and as long as a poet wishes. A bonus is the flexibility of this form in terms of how long or short the poem can be.