u/Mango_Van_Gogh

Hello, I found a site that mentioned possible easter eggs and this was one of them, stating "The initials “LR” (for Lyle Rains), “OR” (for Owen Rubin), “Ly” (for ?), “Mh” (for Morgan Hoff), and “PM” (for Paul Mancuso?) can be found in the program, coded as graphics. According to programmer Owen Rubin, it’s quite possible these can be triggered to appear on the screen!" I was able to confirm that the initials/signature graphics are present in the ROM as sprite graphics and that they're coded as motion-object graphics in the sprite ROMs. They show up through the game’s built-in diagnostic/test mode, not through normal gameplay. At least as far as I can tell, I don't see a normal gameplay/player-accessible trigger.

The working path I used was:

1. Open MAME’s menu with Tab.
2. Go to DIP Switches.
3. Set NEXT TEST = On.
4. Exit the menu.
5. On macOS, press Fn+F2, then Fn+F3.
6. Open DIP Switches again. Service Mode should now be On.
7. Set DIAG TEST = On, then Off, then On, then Off, then On.
8. Let the diagnostic sequence run.

After the sprite/object diagnostic starts cycling, the hidden initials/signature graphics appear in the high sprite-code region. They do not appear as a clean title-card-style message; they appear as part of the diagnostic sprite test, mixed with other diagnostic graphics and sometimes rotated or stylized.

I found that DIAG TEST can be toggled a few more times to continue cycling through the diagnostic sequence. If Service Mode is still On, the sequence restarts from the beginning with the beeps. If Service Mode is Off, it returns to the main game screen.