Yes they are, whatever is in your mind will come up. At the same time though, a lot of things will be similar to others, especially if you are tripping with them in the same environment. There are certain movement that everyone seems to get on their trips, breathing walls, swirling patterns, fractals, and stretching or shrinking of objects. A lot depends on what your looking at, what your thinking at the time of looking at it, and of course the amount of substance your on.
Every trip is going to have it's unique visuals, but you'll be surprised how closely what you see on LSD resembles stuff like ancient tribal artwork. Or the simpsons. Or geometry. It's all one.
I always see ancient tribal artwork in my bathroom for some reason :O I never would've thought that I would see stuff like that on acid before I took it, I've never really thought about ancient tribal artwork before, it's kinda weird and interesting
Last trip I took Aztec geometric patterns transformed in and out of little interconnected meditating Buddhas on a wooden wall. Cool shit. I've wondered if it really matters what psychedelic one takes. I have a friend who has seen shrunken objects only on shrooms, and another friend only sees that on mescaline. It's interesting how different substances affect different people's perceptions.
They're different in the sense that not everyone will see the exact same thing happening.... They're the same in the sense that each drug has a particular profile of possible effects, and each person has a slightly different chemical makeup which slightly alters that profile. If you take acid, you won't see spiders driving taxicabs, unless you're highly schizophrenic before you take the acid. You'll see shimmering shifting colours, fractals based on patterns that you're already looking at, patterns flowing or shifting (wood grain flowing or moving, the patterns on white walls suddenly become visible as an overall thing instead of individual unrelated lumps, tracers flowing off of blowing grass or trees, swirly patterns similar to those left by canoe paddles in water as objects move, etc) Then, most of those effects as I described them could apply to most phenethylamines or tryptamines. Pictures are better at describing what you'll see or feel. Guerillabedlam has a very good thread on psychedelic description through pictures, somewhere.
Its amazing the quality of the visuals, and how real they can be sometimes. One time I was staring at a picture of a band and it looked like the drummers hands were sort of moving up and down, and I was just like ooo acid this is cool. Then all of sudden in full detail, the drummers hands start moving, the foot starts moving, the keyboardist starts moving, and they start playing a song as if there were real miniature people playing a show in front of me, in full real time fluid motion. I went from ooo acid haha, to OMG LSD IS SOME SERIOUS SHIT!
We used to have fun going down to the gym and looking at the tiles in the big shower room. A whole room full of tiles can do some really cool things, starting with breathing and then they can do anything from fractals to dancing. Turning on all the showers, getting naked, covering everything with soap and shooting around on your back is optional, but also fun... Beware of bonked heads.
No, they are not different for everyone. People have different ways of interpreting and and then communicating to others.
Most people will see what are called patterns and trails. Patterns are what some describe as Aztec or tribal looking patterns. Trails are seeing multiples of an item that is moving. If you've ever turned on mouse trails on your computer well that's what they look like. Most people also will see objects move. Like staring at a TV set and then seeing it go up the wall and then back down. You will NOT see things like pink elephants. What you see is the environment around you change in different ways.