The slide represents a problem we have solved in a class.

I asked all students to name one feature of the situation or a physical quantity which might be important for analyzing the situation and put all of them on a board (in the class of 30 students by the end if was tougher and tougher to do so I gave some guidance). Then we started looking for possible connections. The last three slides show some evolution in mapping. I could have present the solution within 7 minutes. However this discussion took about 70 minutes.