Reddish brown, which resembles that of cockroach wings.
Yellow: This variant is made of sweet potato and tapioca, with a golden color similar to that of honey.
References
^J. W. T. Bottema, Sweet potato in Viet Nam: production and markets Page 19 ESCAP Regional Co-ordination Centre for Research and Development of Coarse Grains, Pulses, Roots and Tuber Crops in the Humid Tropics of Asia and the Pacific - 1991 "They are also made into dried pellets (Quang Nam-Da Nang), or half-boiled and made into various cakes: "Banh re", "Banh deo", "Banh thuan", (Thuan Hai province)."