void draw_arrow(int x1, int y1, int x2, int y2, int sz=10);
void draw_x(int x1, int y1, int sz=2);
void draw_t(int x1, int y1, int sz=2);
+ void draw_oval(int x1, int y1, int x2, int y2);
// 3D scene graphs
// Not integrated with shmem because that only affects codecs