It is a general discussion, but without abstracting too much, let's talk about a divertimento.
One technique is to take a significant part of the S., CS. Free part and imitate it among the voices... if we want, it is truly schematic work and almost like copy-paste.
The point is then to ensure that this schematicism does not weigh heavily, so that the entire outline (namely the other voices) must create interest. So how do you "hide" the structure of a divertimento? Good question.
For now, it depends on the material, but I remember that in a fugue Gozzo asked me: "I can't find the structure of the stretto, how did you behave? By ear, freely, however it comes, etc."
In reality, the structure was certainly there, but it had been so "manipulated" and elaborated that it was difficult to truly understand which were the supporting fragments (which had generated those stretti) and which were the filler ones.
Think about laying down identical fragments in the 4 voices, then you start doubling some at the tenth, for others (perhaps in pairs) you change the attack, for the other 2 the tail, then you graft in pieces of the S or CS or vice versa or free part, pauses (why not?).... at a certain point, even you, who did not use colors, after a short while you don't remember precisely, but the divertimento still stands and results to be interesting and proportionate.
It is not certain that it must always be this way, but hiding structures is an art on par with creating them... not to be underestimated. I do not repeat it all the time, but mine are always invitations to reflect rather than true "rules," so much so that in the fugues I will send you, the structure is clearly proclaimed.... (they were didactic fugues)
But it depends, precisely.... "reflect" on the subject.