The designs of the firmas often incorporate ideas from traditional Kongo cosmology, including references the sun circling the Earth and the horizon line, regarded as the division between Heaven and Earth. There are many different designs; some are specific to the mpungu it is intended to invoke, others are specific to a particular casa-templo or to an individual practitioner themselves. Before a ceremony, the firmas are drawn around the room. The creation of these drawings are accompanied by chants called "mambos". Gunpowder piles at specific points of the firma is then lit, with the explosion deemed to attract the attentions of the mpungu.