Good question. Hard to answer. Maybe both?
This, is a modular synthesizer. Also called a eurorack.
Surprisingly enough, people make music with these things.
And it sounds a lot like ...
This.
BUUUUUT
Usually ends up sounding a lot more like...
Realistically speaking though, there aren't any real limits for what your modular system can do.
It's up to your imagination and the way your rig is built.
SOUND WIZARDRY
Is what I call this type of music.
Rather than working with a guitar or piano, which is essentially a fixed sound ( without a pedal board )
You're able to construct the instrument of your dreams out of different modules.
Above is an example of a module built by the company Pittsburgh. This module is of an oscillator which is also known as one of the main generators of sound.
A module to a eurorack synthesizer is like an organ to the human body.
Human body is built of many different systems that do different tasks in the body, brain, heart, lungs, colon, genitals.
Euro racks are the same way, artificially.
With a euro rack, you'll want a sound generator ( an oscillator ) and you may also want to add an ADSR ( attack, decay, sustain, and release) module.
Of course you would also want to integrate a way for the sound to be triggered. So you would want to get a clock, or trigger module.
And how will these modules communicate with each other?
Right! through patch cables ( allow the blood a.k.a electricity to flow )
CONCLUSION
Modular synthesis is both as hard and as easy as it looks.
If you're confused/intrigued by any of this.
Don't worry, I'll be posting more articles going more in depth.
In the mean time, there is free software called VCV rack worth checking out.
If you're a first timer, it will most likely be frustrating and confusing.
I recommend researching modular synthesis basics through the internet to get you familiarized with different terms before taking the plunge