Specifically my Commodore Vic 20, C16, and C64 machines
We shall compare the machines side by side, to see the subtle case differences between each machine, because they are not the same despite what you remember...
Top and bottom comparison
They look similar from above and below, apart from the colour obviously, the Vic 20 is missing a strip of plastic at the top left of the bottom case
Side ports
The left side of the machine is plain on all three machines, the right side has different ports, one joystick port for the Vic 20, two ports for the other machines, but the C16 has the mini DIN type sockets and squeezes in a reset button. Also the C16's power switch is rotated 90 degrees and its power socket is smaller
Rear ports
The serial and monitor sockets are the same on each machine, the Vic 20 and C64 has the same user and cassette ports. But the Vic 20 doesn't have an RF out socket, and all three machines have different cartridge ports. You can see the Vic 20 doesn't have the case lowered underneath its cartridge port. The C16 has a much smaller board inside
Model badges
The badge is the same size on each machine, The C16 has the rainbow emblem rotated. To me it would make more sense to start the rainbow with the red coming in from the left
Power LEDs
The power LED is the same on each machine
Keyboards
Vic 20 keyboard close-ups
C16 keyboard close-ups
C64 keyboard close-ups
The keyboards have the same number of keys in the same style with the bottom two rows shifted over to the left slightly, which always annoyed me, the C16's F8 key is relabelled HELP
Model labels
The model labels are similar for the Vic 20 and C64, the C16 has a different style of label entirely
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