// S = S0 * f(L/Lmin) where f(x) = 1 + (7 * 2/Pi * atan(x/5))

 // S = S0 * f(L/Lmin) where f(x) = 1 + (7 * 2/Pi * atan(x/5))
+    // The above formular gives too short segments when Lmax/Lmin is too high
+    // because by this formular the largest segment is only 8 times longer than the
+    // shortest one ( 2/Pi * atan(x/5) varies within [0,1] ). So a new formular is:
+    // f(x) = 1 + (x/7 * 2/Pi * atan(x/5))