LOL, was thinking the same, but didn't want to create a new 4D category ... I have the suspicion it won't be very popular :)
So let's just acknowledge it from the point onward where it has been projected into 3D space cough
The formulas are (as usual) not mine, I had them somewhere in my 'maybe someday I will do this' copy&paste collection. I will try to remember where it originally came from. The source bits I got are JS so I guess I got it either from JSfiddle, Codepen or Processing (love it).
Several examples I looked at treat it exactly the same way 3D projection is done. You just extend the matrix by one more parameters.
'w' in my example, other call it 't' or whatever they like.
Then you will have noticed this part in the code:
//Projects 4D to 3D
loc[3] -= Camera.w/Camera.wFocalLength
loc[0] = -loc[0]/loc[3]*Camera.wFocalLength
loc[1] = -loc[1]/loc[3]*Camera.wFocalLength
loc[2] = -loc[2]/loc[3]*Camera.wFocalLength
Looks familiar, doesn't it? So instead of mashing up X and Y with the distance Z (and FOV, camera, etc.) you now do exactly the same to X,Y & Z ... mashing them up with W (or T) instead. After that you have the 3D projected data and can continue as usual. Somewhere I saw a video where a guy morphed the 3D model of a horse into 4D ... one freaky looking horse I tell you ... (done in Rhino 3D modeller).
Uhhh, there is so much to tinker in there .... long weekend coming up ;)
Oh, and initially I was going to call it Hypercube (-> TinkerCube), but then I liked Tesseract better (ASSEMBLE AVENGERS).
So ... in a way you could extend the whole thing now to 5D, 6D, etc ... but my brain already gets confused with the 4D one, LOL.
Still trying to wrap my head around the left/right, up/down shifting of that inner cube. Sometimes my eyes can't decide which one to follow.
But in the end I believe you probably know better what is going in there than me ... I just throw stuff together, oh @that_name_will_figure_it_out ;)