[This is the 17th of my April A-Z Challenge series of posts on Symbols, Glyphs, and Sigils. Each day I'll try to include some material that old-school role-playing gamers will find useful, but I can't guarantee that there won't also just be a few posts filled with weirdness for the sake of weirdness....]
"Quincunx" is one of those words that has branched out into many meanings in many fields. From the Latin phrase for the fraction five twelfths, it originally referred to a Roman coin worth 5/12 of their standard bronze denomination. They used a pattern of five dots, in the standard "dice" pattern (a square of 4 dots surrounding the 5th central dot), on that coin. Soon that abstract pattern became known as a quincunx in heraldry, and it eventually became popular in various counter-cultural circles as a covert tattoo design.
However, probably the most widespread meaning of the word quincunx is in astrology, where it refers to an angular aspect of 150 degrees (i.e., a separation of 5/12 of a great circle) between two planets. The purple "sawhorse" glyph above is the standard symbol for this aspect.
Because 5/12 is kind of an oddball fraction -- especially in comparison to the more "harmonic" fractions of 1/12, 2/12, 3/12, 4/12, and 6/12 -- the quincunx was often thought of as the red-headed stepchild of the aspects and given the name "inconjunct." Poor quincunx...
When two planets are in a quincunx aspect with one another, it's supposed to be not overwhelmingly positive or negative. Because the two zodiac signs are so different from one another (just shy of a crisp opposition), it's thought that the 2 planets just don't know how to relate to one another. Not so much direct conflict as uneasy friction. Maybe it's the astrological equivalent of this:
For some reason, the idea of the two "inconjunct" planets being thrust together with no common ground makes me think of the surrealists and their fondness for making odd juxtapositions between disparate items. Even though the surrealists often said that the best juxtapositions were the most distant and jarring, I think the coolest ones are those with SOME commonality between the ideas. I think that's why I like the semi-realistic paintings of Dali, Ernst, and Man Ray, but I don't connect as much to the most abstract end of the spectrum (Miro, Kandinsky, Duchamp) or to the absurdist performance stuff (Ubu Roi, John Cage).
In my letter C post, I mentioned something similar with my own goal of moderation in designing settings and adventures for fantasy role-playing: not too much Weird... but not too little, either. Players may need some discrete "stepping stones" that connect their own experiences to this Other World. Though of course the occasional inexplicable non sequitur can be fun, too! :-)