Usagi's footage of greyscale green brings back a warm & fuzzy memory. Most gootubers just show color monitors because color monitors are free compared to what they were in the day. Greyscale green is a rarely seen color scheme, but it briefly appeared in lion history during an overall simpler time. All we had in those days were different shades of green for different colors. A greyscale green interface today would be quite difficult. The xgamma command can only adjust gamma. The 4K LG can adjust color balance but not turn off a channel. It took some doing just to make X11 draw B&W for outdoor use. It would almost be easier to capture HDMI & translate it to green in a raspberry pi for display.