This is for a PET 2001 (at least 8K), well known for having chartacter graphics only.
The program runs without any noticible effects.
10 A=2048+62
20 READ N:IF N=0 THEN END
30 FOR I=0 to 4:READ B(I):NEXT
40 FOR K=1 TO N
50 FOR I=0 TO 4:POKE A+I,B(I):NEXT
60 A=A+128
70 NEXT
80 GOTO 20
100 DATA 2,0,0,0,0,0
110 DATA 1,0,0,126,0,0
120 DATA 1,0,1,255,128,0
130 DATA 1,0,3,255,192,0
140 DATA 1,0,7,255,224,0
150 DATA 1,0,15,255,240,0
160 DATA 1,0,31,255,248,0
170 DATA 2,0,63,255,252,0
180 DATA 2,0,127,255,254,0
190 DATA 2,0,255,255,255,0
200 DATA 3,1,255,255,255,128
210 DATA 3,3,255,255,255,192
220 DATA 11,7,255,255,255,224
230 DATA 3,3,255,255,255,192
240 DATA 3,1,255,255,255,128
250 DATA 1,0,255,255,255,0
260 DATA 1,0,127,255,254,0
270 DATA 1,0,63,255,252,0
280 DATA 1,0,31,255,248,0
290 DATA 1,0,15,255,240,0
300 DATA 1,0,3,255,192,0
310 DATA 1,0,0,126,0,0
320 DATA 2,0,0,0,0,0
330 DATA 0
(I have no idea, where you would look for the easter egg on a real PET 2001, but my emulator got a memory map visualization, just yestarday.)
Have you done or found any easter eggs lately?