qmk-firmware/keyboards/lets_split/rev1/rev1.h

#pragma once

#include "quantum.h"

#define LAYOUT( \
	L00, L01, L02, L03, L04, L05, R00, R01, R02, R03, R04, R05, \
	L10, L11, L12, L13, L14, L15, R10, R11, R12, R13, R14, R15, \
	L20, L21, L22, L23, L24, L25, R20, R21, R22, R23, R24, R25, \
	L30, L31, L32, L33, L34, L35, R30, R31, R32, R33, R34, R35 \
	) \
	{ \
		{ L00, L01, L02, L03, L04, L05 }, \
		{ L10, L11, L12, L13, L14, L15 }, \
		{ L20, L21, L22, L23, L24, L25 }, \
		{ L30, L31, L32, L33, L34, L35 }, \
		{ R00, R01, R02, R03, R04, R05 }, \
		{ R10, R11, R12, R13, R14, R15 }, \
		{ R20, R21, R22, R23, R24, R25 }, \
		{ R30, R31, R32, R33, R34, R35 } \
	}

#define LAYOUT_ortho_4x12 LAYOUT