This question is based on selected poems from D. Ker, C. Maduka et al (eds.): New Poetry from Africa, Wole Soyinka (ed.): Poems of Black Africa, K.E. Senanu and T. Vincent (eds.): A Selection of African poetry and E.W. Parker (ed.) A Pageant of Longer Poems.

'I hear your call
I hear if far away
I hear it break the circle'
The device in which the first two words of the lines above from Okara's 'The Call of the River NUN' are invaried while the rest very is called