/** fill a trapezoid whose top and bottom edges are horizontal */
public abstract void fillTrapezoid(int x1, int x2, int y1, int x3, int x4, int y2, int color);
/** fill a trapezoid whose top and bottom edges are horizontal */
public abstract void fillTrapezoid(int x1, int x2, int y1, int x3, int x4, int y2, int color);