There are several opinions and theories about what mokko-mon designs are based on, such as a theory that suggests that mokko-mon is a design of a cross-section of a gourd or the gourd itself, and an opinion that suggests that mokko-mon is a design of a bird's nest.
木瓜紋は、瓜の切り口や瓜そのものを図案化したものとする説や鳥の巣とする説など何を図案化したのかの見解や説が幾つかある。