xfig also has one of the few implementations of x-splines (x means "cross" here, like "pedestrian xing", unrelated to the X window system). I find x-splines ver

xfig also has one of the few implementations of x-splines (x means "cross" here, like "pedestrian xing", unrelated to the X window system). I find x-splines very nice and intuitive. Here's a little x-spline implementation I made: https://jordi.platinum.edu.pl/xsplines/splines.html https://jordi.platinum.edu.pl/xsplines/splines.html