I would like to shade a specific region in a polar plot using GNUPlot. This region is bounded by limits in R (r1, r2) and Theta (t1, t2), so the final shape is an annulus segment defined by only 4 ...

I have created the gnuplot, but the problem is that it disappears immediately. I tried different solutions proposed in other threads, but none of them worked. Solution 1: comment the line bf.append...