Symmaic is “same” gender attraction for non-binary people. For example, a demigirl attracted to other demigirls may be considered symmaic. This may be used interchangebly with gai in some cases, however gai people may be attracted to binary genders that are considered their similars (example: a demiboy attracted to demiboys and men) while symmaic might only refer to other non-binary genders, depending on who you ask.
The opposite is contraic.
Flag
The flag was coined by Pride-Flags on Deviantart. It uses purple to represent the median between masculinity and femininity, and yellow and white to represent non-binary attraction.
History
Symmaic was coined on May 22, 2018 by Tumblr user Identity-Workshop.[1]
Etymology
It uses the prefix “sym” as in “symmetry”, meaning “same”.
Resources
https://www.deviantart.com/pride-flags/art/Symmaic-2-750152928