On day of Dussehra practice of the physical act of worship for Goddess transforms the expressed Bhaav of an embodied soul into an unexpressed one and thereby helps in maintaining its stability.
A. Placing an idol of Goddess Aparajita on a rangoli of an octapetalled figure signifies Her ability to control the eight directions :
Aparajita is a destroyer form of Goddess Durga. Aparajita manifests from the womb of the earth with the help of the absolute earth element. This manifestation of Goddess Aparajita is for the sake of souls on the Earth. This form of the Goddess which establishes itself on the throne of the eight petals carries a trident and with the help of God Shiva, seeking assistance from the Devatas of directions and the Devtas of the premise, destroys the demoniacal energies.
When Goddess Aparajita sitting on the throne of the eight petals emerges from the womb of the earth in response to prayers of devotees, the Devtas of the eight directions also manifest to welcome Her. The tips of the eight petals represent these eight Devtas. The destroyer frequencies generated from creation of Goddess Aparajita through the medium of the eight Devtas get emitted as red coloured light frequencies and destroy the accumulated Raja-Tama energy purifying the atmosphere to help people on the earth to lead an obstacle-free life.
B. Since the leaves of Shami are good conservers of energy worship of Goddess Aparajita is carried out near a Shami tree :
The Aparajita form of Goddess Durga is worshipped near the Shami tree because Shami leaves are good conservers of energy and they conserve the energy of Aparajita that manifests in the form of fountains, for long periods. People benefit from this conserved energy of Goddess Aparajita by preserving these leaves in their homes.