If you join points with a tilde (~), the graph tool will draw a smoothed line joining the points.
For example, if you enter (-10,-4)~(-5,3)~(1,-1)~(6,8)~(10,-4) as your function, the graph tool will draw this graph.
You can mix ~ and + in the same function.
(-10,-4)~(-5,3)+(1,-1)~(6,8)~(10,-4)
The smoothed curves do not have to be left to right. In other words, they do not need to represent a function.
(-10,-4)~(-5,3)~(1,-1)~(6,8)~(10,-4)~(6,-10)~(-5,5)
