.00truecm> \setplotarea x from 0 to 00, y from 0 to -0  \setlinear \plot 0 0 00 0 / \plot 0 0 0 -0 / \put {\vector(0,0){0}} [Bl] at 00 0 \put {\vector(0,0){0}} [Bl] at 0 0  \setquadratic \circulararc 000 degrees from 0.00 0 center at 0 0 \circulararc 000 degrees from 0.00 0 center at 0 0 \circulararc 000 degrees from 0.00 0 center at 0 0  \setlinear \plot 0 0  0.0 -0.0000 / \plot 0 0  0.00 -0 / \plot 0 0  0.000 0.0 /  \put {${\rm p}^\mu$} at 0 0.0 \put {${\rm q}^\mu$} at 00.0 0 \put {$\scripts