Recently, I've been hearing a good deal about hardware tricks. For instance, the YouTuber Ahoy (see A Brief History of Graphics) mentions that some game programmers resorted to "hardware tricks" to diversify the gamut of colors on the screens of console systems using mode 7 (I'm assuming that's mode 07h in Assembly). Then I read about some kind of "graphical trickery" in Doom (see the Reception section on the Wiki page for Doom here) to give the illusion that you are in a world with heights and elevations. Does that also mean some kind of hardware trickery? What is a hardware trick and is there such a thing as a software trick?
EDIT: Just to be clear, though I do have a basic idea of what a "hack" or a "trick" is, the emphasis really is on the "hardware" part, but people got sidetracked by the former. It is my understanding that the "hardware" part comes in when we discuss things like video memory (memory addresses) as part of the larger memory component in a machine, and there is a sea of numbers involved to be manipulated to represent 2D (faux 3D) geometries. Am I correct on that last one?