10 CLV:VIDEO 3
20 L=3:J=L-1:M=L*L:N=M-1
30 FOR I=0 TO N
40 [I]=(I+1)%M
50 NEXT
60 GSB @P
70 X=N
80 FOR I=1 TO 100
90 K=RND(4):GSB @M:S=S+1
100 NEXT
110 GSB @P
120 @LOOP
130 K=INKEY()-28
140 IF K<0 OR K>3 GOTO @LOOP
150 S=S-1:GSB @M:GSB @P
160 GOTO @LOOP
170 @M
180 Z=X-(K=0)*(X%L>0)+(K=1)*(X%L<J)
190 Z=Z-(K=2)*(X/L>0)*L+(K=3)*(X/L<J)*L
200 Y=[X]:[X]=[Z]:[Z]=Y:X=Z
210 RTN
220 @P
230 CLS
240 FOR I=0 TO N
250 Z=[I]
260 IF Z ?HEX$(Z); ELSE ?" ";
270 IF I%L=J ?
280 NEXT
290 ?:?S
300 RTN