press space to create a line it will ask: x,y (0,0 for middle) slope (m) type integer or decimal color (hue) effect: 0: off, any integer 1 or above: decimals: rainbow
a to toggle seeing the lists 0 to delete all if you're unfamiliar x and y are coordinates on the grid slope how steep the line will be. i'm pretty sure you know what color is pattern is multiplied by 50 to make stripes, but it will be more of a gradient if you enter a decimal, and it will go back the rainbow if it is negative.
