100 REM "4 nested for loops"
110 PRINT "4 nested 4 loops"
120 Z=0
200 FOR I=1 TO 2
210 FOR J=1 TO 2
220 FOR K=1 TO 2
230 FOR L=1 TO 2
240 Z=Z+1
250 PRINT Z;" :",I,J,K,L
260 NEXT L
270 NEXT K
280 NEXT J
290 NEXT I
300 PRINT "16 lines should show here" 
310 END