# Add the sugar
and the egg into the margarine, mix.
# Add the starch and the flour
into the mixture little by little.
# Add the vanilla and the sodium bicarbonate finally to get smooth dough.
# Divide the dough into 2 pieces. Add the cocoa
into one of them, knead.
# By this way you get 1 piece of white dough and black one also.
# Pick half walnut
sized pieces from the white dough, and roll them between your palms.
# Pick also half walnut
sized pieces from the black dough and roll them also.
# Stick the pieces with the other ones, but dont mix their colours. Repeat this act until whole of the dough finishes.
# Place them onto the greased oven tray. Bake in the 392 F oven which is preheated well, for 20 minutes.