Prep for work tomorrow

Tomorrow I'm to deliver a short session as part of a workshop for tutors about RARPA (sorry for the boring link, but I really did try to find the most interesting one!) My bit is for the craft tutors, and needed a simple activity to illustrate the principles.
"Cut No Corners" will have a simple objective: cut a circle from a piece of paper. I have looked out all my circle cutting tools and realise that none is quite perfect and all have a slight drawback. The tutors will have to write their own SMART (Specific, Measurable, Achievable, Recordable, Timely) objectives as part of the session and it could be that they will make it more complicated to bring in a bit of differentiation (what an odd website on which to find that link!!) Maybe the challenge will be to cut a circle of a specific size, to cut the hole rather than the circle, or to evaluate the different methods of cutting and produce a tipsheet.
It's certainly made me think about which I'd use and under what circumstances.

What's your favourite means of cutting a circle? Did you realise the hoops tutors have to jump through these days to earn their crust?