The "zism" was invented as a graphic design in 1983. In those days I was playing around with trying to do abstract cartoons. An early version of it appeared with a bunch of other simple gesture drawings on a cover of Throttle I did in 1984.
For whatever reasons, I liked drawing zisms for several years. To me it suggested threes: The past, present and future. Yes, no and maybe. Black, white and gray. Father, son and holy ghost, etc. I also thought of it as a cartoon representation of time moving. It was meant to look like a logo, but sort of a joke on that power style. A mock icon.
Anyway, the zism image was used more or less as a logo for the SLANT, especially in its early days. I still like how the old ones like these look, but I don't draw them anymore. Here's a field of them.