Question about multiplication in project 4 + technical issues


i’m currently working on project #4 and i have two questions:

  1. in the multiplication circuit, are we supposed to use a tree of only 4:2 adders and a single csa? or can we use any amount of 4:2 and csas?

  2. i’ve been experiencing some technical difficulties with logisim for a while now, but it’s gotten really bad in the past few days - it started with just multicoloured wires, but now
    circuits that worked completely fine are suddenly not working anymore (with certain outputs randomly marked with X instead of 0 or 1), and then miraculously coming back to life. it’s also been working increasingly slowly, to the point of freezing every time i try to work on the project.
    i’ve tried resetting the simulation and a few other things but nothing i do seems to directly fix the issue.
    have i possibly done something wrong with one of the circuits or is this a bug with logisim? how can i fix this ?

thank you

Questions of the form “are we allowed to” do not belong to our discipline.
The question should be “is it useful” or “does it lead to an efficient design”!

The goal is to design a multiplier with delay that is O(\log n) and cost O(n^2).
Your design is for n=8, so talking about asymptotics is a bit silly, but we do want the method to be easily extendible to every n with the above delay and cost.