Move your mouse around. If the red dot is touching the blue line, then it should turn green. Press the one and two keys to set the points of the line. No "If touching" scripts are used here. I don't know how other people make detection scripts, but an idea popped into my head, i tried it, and it worked. Change the line thickness with the slider. If you want to use this script, even though you can probably find a better one, you can as long as you give credit. @k0stya for the "distance to script" which i modified.