void draw_rect(frontend *fe, int x, int y, int w, int h, int colour);
void draw_line(frontend *fe, int x1, int y1, int x2, int y2, int colour);
void draw_polygon(frontend *fe, int *coords, int npoints,
void draw_rect(frontend *fe, int x, int y, int w, int h, int colour);
void draw_line(frontend *fe, int x1, int y1, int x2, int y2, int colour);
void draw_polygon(frontend *fe, int *coords, int npoints,