COMMENT ⊗   VALID 00002 PAGES 
RECORD PAGE   DESCRIPTION
 00001 00001
 00002 00002	BEGIN "X"
 00003 ENDMK
⊗;
BEGIN "X"
	REQUIRE "DPYIII[SYS,BGB]" SOURCE_FILE;
	INTEGER ARRAY DPYBUF[0:1000];
	REAL X,Y;

	DPYSET(DPYBUF);
AIVECT(-500,-500);
AVECT(+500,-500);
AVECT(+500,+500);
AVECT(-500,+500);
AVECT(-500,-500);
AIVECT(-500,0);AVECT(500,0);
AIVECT(0,-500);AVECT(0,500);

	FOR X ← -10 STEP 0.1 UNTIL +10 DO
BEGIN
	Y ← ((4*X + 9)*X↑2 - 2)*X + 1;
	AVECT(X*50,Y*2);
END;	DPYOUT(0);
	INCHRW;
END;