The game's board in C follows the behavior and tables of these files of MAME 0.289
(https://github.com/mamedev/mame), each under the BSD 3-Clause License below:

- src/mame/konami/tmnt.cpp: the board of Teenage Mutant Ninja Turtles (its memory map, inputs and
  interrupts, its sound board, the priority of its layers, the shadows, the title music's sample);
  copyright Nicola Salmoria.
- src/mame/konami/k052109.cpp and k051960.cpp: the K052109's tile layers and the K051960's sprites;
  copyright Fabio Priuli, Acho A. Tang, R. Belmont.
- src/emu/tilemap.cpp and drawgfx.cpp, src/lib/util/palette.cpp: what the video takes of them; copyright
  Nicola Salmoria, Aaron Giles.
- src/devices/sound/k007232.cpp: the K007232; copyright Nicola Salmoria, Hiromitsu Shioya.
- src/devices/sound/upd7759.cpp: the uPD7759; copyright Juergen Buchmueller, Mike Balfour, Howie Cohen,
  Olivier Galibert, Aaron Giles.

The ROM set's layout, which the game's first run reads, comes from tmnt.cpp too.

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