For the Jewish people there is no place more holy than the remaining Western Wall of the ancient temple of Jerusalem. Prayers and pleas are written on slips of paper and fitted between the stones. These cracks are seen to serve as a portal to the Almighty and the wall is packed with thousands of these messages, from many thousands of hands across the centuries.
Collaged with commercial fabrics, thread. No special materials are required to send a prayer.
An interesting interpretation for a portal.