Sample context diagram
A rectangle labelled Entity A has an arrow (labelled Data flow 1) that is pointing to a circle labelled System. A second rectangle labelled Entity B has an arrow (labelled Data flow 3) that is pointing to the circle labelled System. An arrow (labelled Data flow 2) is pointing from the circle labelled System to the rectangle labelled Entity B. A third rectangle labelled Entity C has an arrow (labelled Data flow 5) pointing to the circle labelled System. An arrow (labelled Data flow 4) is pointing from the circle labelled System to the rectangle labelled Entity C.