Hi Pilou - after trying your solution one other kind of general problem sort of jumps out at me which is such a heavy reliance on mirroring multiple times.

That level of mirroring tends to require a lot more planning and is kind of less of a dynamic sketching/drawing kind of feel...

When you look at the solution I do in MoI, it seems to be to stay more recognizable and sort of "whole" during the entire process.

Your one in SketchUp feels really quite a lot less like natural drawing, to me at least!

- Michael