@Markiyan Hirnyk What do you allow yourself, what is my name in the forum? Where all my correspondence with Kitonum in that section?
I urge you to behave properly and to eliminate all violations committed by you.

@Markiyan Hirnyk  And where are the other examples of their the links?  

Again in the form of pictures.

@Markiyan Hirnyk  Who is Alexei Ivanov?

Two more similar examples.

@Markiyan Hirnyk 

You, as always, "I heard a bell, but do not know where it is." Is this animation associated with the program  SPIRAL.mw, the moderator  You ours? 

@Kitonum Compilation based on your answer and Thomas Richard

a := [1, 2, 3, 4, 5];
k := parse(cat(op(a)));
whattype(k);
k/5;

@Bendesarts 

I think you yourself can easily get the kinematics of any point with texts of my programs in the first message. For example, rhs (a1), rhs (a2), rhs (a3) correspond to the coordinates of the green point (x1, x2, x3), then

 ((rhs (a1) (s + h) - rhs (a1) (s)) ^ 2+ (rhs (a2) (s + h) - rhs (a2) (s)) ^ 2+ (rhs (a3) (s + h) - rhs (a3) (s)) ^ 2)) ^ 0.5 / h  

will speed along the trajectory of the green point on the rules of numerical differentiation. Similarly calculate the speed of the other points. The second derivative corresponds to acceleration. That is, if we know the coordinates of any point of the mechanism at any time, we can calculate the necessary qualities: any angles, any velocity along any axis, and so on. If you remember, I was trying to ask you: what is the source of such huge trigonometric expressions in your messages?
The presented work (.pdf) was written in Russian, you can try is to translate it using Google-translator, or any other way. I have plans to write more details in English, but this takes time.

@Carl Love  Very grateful to you, especially for the English.

 Another example of different "input links".  Four-bar mechanism.

@Thomas Richard  Thank you very much for such a detailed answer. It seemed better to continue only with Maple.
(As for my Maple drawing(s), of course, it's not modeling, it's simply a visualization of a calculations.)

@Bendesarts Could you briefly tell about the problem in connection with the decision which arose such expressions?

More versions of cam mechanisms

  @tomleslie Example with Isolate: all solutions of a system of polynomial equations.

example_with_isolate.mw 

@tomleslie Root Finding [Isolate] works with Gröbner bases and thus find all the solutions of a polynomial system (when replacing variables for the sum of the real and the imaginary part find all real and all complex solutions. In Mathematica it seems, Nsolve).  On this basis, the system can be examined for compatibility  and an infinite number of solutions. But a polynomial systems only.

For another type of systems is a very powerful tool is DirectSearch [SolveEquations].

If there is a continuous infinite set of solutions recommend Draghilev's method.

@tomleslie  Excuse me, I do not know English, but I realized that this is not a solution, and to the answer to question Muhammad Usman has nothing to do.