10 GOSUB 50000
20 PRINT CHR$(27)+"H";CHR$(27)+"E";CHR$(27)+"f"
30 X%=360: REM X POS
40 V%=0: REM BRUSH SIZE
50 Y%=128: REM Y POS
60 P%=1:REM BRUSH POSITION (DOW/UP)
70 F%=1: REM BRUSH STATE (INK/ERASE)
80 LET C$=INKEY$
90 IF C$="A" OR C$="a" AND X%>0 THEN LET X%=X%-1
100 IF C$="S" OR C$="s" AND X%<718 THEN LET X%=X%+1
110 IF C$="W" OR C$="w" AND Y%<256 THEN LET Y%=Y%+1
120 IF C$="Z" OR C$="z" AND Y%>8 THEN LET Y%=Y%-1
130 IF C$="I" OR C$="i" THEN LET F%=1: REM INK ON
140 IF C$="E" OR C$="e" THEN LET F%=0: REM INK ERASE
150 IF C$="C" OR C$="c" THEN PRINT CHR$(27)+"H";CHR$(27)+"E"
160 IF C$="D" OR C$="d" THEN LET P%=1
170 IF C$="U" OR C$="u" THEN LET P%=0
180 IF C$="T" OR C$="t" THEN GOSUB 260
190 IF C$="2" THEN V%=1
200 IF C$="1" THEN V%=0
210 IF C$="F" OR C$="f" THEN 360
220 IF P%=0 THEN GOTO 80
230 CALL PLOT (X%,Y%,F%)
240 IF V%=1 THEN 290
250 GOTO 80
260 A%=X%/8:B%=INT((256-Y%)/8):PRINT CHR$(27)+"e";
270 PRINT CHR$(27)+"Y"+CHR$(32+B%)+CHR$(32+A%);:INPUT "",T$:PRINT CHR$(27)+"f";
280 RETURN
290 A%=X%-1:B%=X%+1:C%=Y%-1:D%=Y%+1
300 IF X%>0 THEN CALL PLOT (A%,Y%,F%)
310 IF X%<718 THEN CALL PLOT (B%,Y%,F%)
320 IF Y%<255 THEN CALL PLOT (X%,D%,F%)
330 IF Y%>0 THEN CALL PLOT (X%,C%,F%)
340 GOTO 80
350 G%=F%
360 FOR Z=1 TO 25
370 G%=(G%+1) AND 1
380 CALL PLOT (X%,Y%,G%)
390 FOR Y=1 TO 50:NEXT Y
400 NEXT Z
410 GOTO 80
50000 MEMORY &HBFFF:PLOT=&HC000:A=PLOT:E=0
50010 RESTORE 50120
50020 FOR F=0 TO 14
50030 S=0
50040 FOR G=0 TO 7
50050 READ X$:X=VAL("&H"+X$)
50060 S=S+X:POKE A,X:A=A+1:NEXT
50070 READ X$:IF S<>VAL("&H"+X$) THEN E=E+1:PRINT "ERROR IN LINE ";10*(F+5012)
50080 NEXT
50090 IF E=0 THEN RETURN
50100 PRIMT E; "ERROR";:IF E=1 THEN PRINT ELSE PRINT "S"
50110 STOP
50120 DATA 0A,32,7C,C0,4E,23,46,21,250
50130 DATA CF,02,A7,ED,42,D8,ED,43,4AF
50140 DATA 78,C0,EB,5E,23,56,7A,A7,41B
50150 DATA C0,93,3D,5F,ED,53,7A,C0,469
50160 DATA F3,ED,73,7D,C0,31,9D,C0,51E
50170 DATA 01,36,C0,CD,5A,FC,E9,00,403
50180 DATA ED,7B,7D,C0,FB,C9,2A,7A,50D
50190 DATA C0,29,11,00,B6,19,5E,23,24A
50200 DATA 56,7B,E6,F8,CB,27,CB,12,47E
50210 DATA 47,7B,E6,07,B0,5F,2A,78,360
50220 DATA C0,45,7D,E6,F8,6F,EB,19,4D3
50230 DATA 78,E6,07,3C,47,AF,37,1F,2ED
50240 DATA 10,FD,47,3A,7C,C0,A7,20,391
50250 DATA 05,78,2F,A6,77,C9,3D,78,347
50260 DATA 20,03,B6,77,C9,AE,77,C9,407