theta

Polar coordinate plots are by default oriented such that theta = 0 is on the right side of the plot, with theta increasing as you proceed counterclockwise so that theta = 90 degrees is at the top. set theta allows you to change the origin and direction of the polar angular coordinate theta.

     set theta {right|top|left|bottom}
     set theta {clockwise|cw|counterclockwise|ccw}

unset theta restores the default state "set theta right ccw".