Patterned waling in African Folk building

In 1955 I spent some time at Kota Kota on the western shore of Lake Nyasa where I was fortunate to have as my guide Shehe Khalidi Bin-Amrani, a fine old Yao schoolmaster who, when I first met him, was busily teaching his pupils to read selections of the Koran from handled boards. His father, he told me, was born at Lindi, an important centre of the slave trade from where a well-defined trade route led to Lake Nyasa, but he eventually settled at Kota Kota and led the Arab traders in search of slaves. Khalidi Bin-Amrani actually took part in the last raids.