54   GLfloat angle, da;  in gear()  local
61   da = 2.0 * M_PI / teeth / 4.0;  in gear()
75       glVertex3f(r1 * cos(angle + 3 * da), r1 * sin(angle + 3 * da), width * 0.5);  in gear()
82   da = 2.0 * M_PI / teeth / 4.0;  in gear()
87     glVertex3f(r2 * cos(angle + da), r2 * sin(angle + da), width * 0.5);  in gear()
88     glVertex3f(r2 * cos(angle + 2 * da), r2 * sin(angle + 2 * da), width * 0.5);  in gear()
89     glVertex3f(r1 * cos(angle + 3 * da), r1 * sin(angle + 3 * da), width * 0.5);  in gear()
102       glVertex3f(r1 * cos(angle + 3 * da), r1 * sin(angle + 3 * da), -width * 0.5);  in gear()
110   da = 2.0 * M_PI / teeth / 4.0;  in gear()
114     glVertex3f(r1 * cos(angle + 3 * da), r1 * sin(angle + 3 * da), -width * 0.5);  in gear()
115     glVertex3f(r2 * cos(angle + 2 * da), r2 * sin(angle + 2 * da), -width * 0.5);  in gear()
116     glVertex3f(r2 * cos(angle + da), r2 * sin(angle + da), -width * 0.5);  in gear()
128     u = r2 * cos(angle + da) - r1 * cos(angle);  in gear()
129     v = r2 * sin(angle + da) - r1 * sin(angle);  in gear()
134     glVertex3f(r2 * cos(angle + da), r2 * sin(angle + da), width * 0.5);  in gear()
135     glVertex3f(r2 * cos(angle + da), r2 * sin(angle + da), -width * 0.5);  in gear()
137     glVertex3f(r2 * cos(angle + 2 * da), r2 * sin(angle + 2 * da), width * 0.5);  in gear()
138     glVertex3f(r2 * cos(angle + 2 * da), r2 * sin(angle + 2 * da), -width * 0.5);  in gear()
139     u = r1 * cos(angle + 3 * da) - r2 * cos(angle + 2 * da);  in gear()
140     v = r1 * sin(angle + 3 * da) - r2 * sin(angle + 2 * da);  in gear()
142     glVertex3f(r1 * cos(angle + 3 * da), r1 * sin(angle + 3 * da), width * 0.5);  in gear()
143     glVertex3f(r1 * cos(angle + 3 * da), r1 * sin(angle + 3 * da), -width * 0.5);  in gear()