qmk_firmware/keyboards/niu_mini/niu_mini.h

#ifndef NIU_MINI_H
#define NIU_MINI_H

#include "quantum.h"

#define LAYOUT_mit( \
	k00, k01, k02, k03, k04, k05, k06, k07, k08, k09, k0a, k0b, \
	k10, k11, k12, k13, k14, k15, k16, k17, k18, k19, k1a, k1b, \
	k20, k21, k22, k23, k24, k25, k26, k27, k28, k29, k2a, k2b, \
	k30, k31, k32, k33, k34,    k35,   k37, k38, k39, k3a, k3b \
) \
{ \
	{ k00, k01, k02, k03, k04, k05, k06,   k07, k08, k09, k0a, k0b }, \
	{ k10, k11, k12, k13, k14, k15, k16,   k17, k18, k19, k1a, k1b }, \
	{ k20, k21, k22, k23, k24, k25, k26,   k27, k28, k29, k2a, k2b }, \
	{ k30, k31, k32, k33, k34, k35, KC_NO, k37, k38, k39, k3a, k3b } \
}

#define LAYOUT_grid( \
	k00, k01, k02, k03, k04, k05, k06, k07, k08, k09, k0a, k0b, \
	k10, k11, k12, k13, k14, k15, k16, k17, k18, k19, k1a, k1b, \
	k20, k21, k22, k23, k24, k25, k26, k27, k28, k29, k2a, k2b, \
	k30, k31, k32, k33, k34, k35, k36, k37, k38, k39, k3a, k3b \
) \
{ \
	{ k00, k01, k02, k03, k04, k05, k06, k07, k08, k09, k0a, k0b }, \
	{ k10, k11, k12, k13, k14, k15, k16, k17, k18, k19, k1a, k1b }, \
	{ k20, k21, k22, k23, k24, k25, k26, k27, k28, k29, k2a, k2b }, \
	{ k30, k31, k32, k33, k34, k35, k36, k37, k38, k39, k3a, k3b } \
}

// Used to create a keymap using only KC_ prefixed keys
#define KC_KEYMAP( \
	k00, k01, k02, k03, k04, k05, k06, k07, k08, k09, k0a, k0b, \
	k10, k11, k12, k13, k14, k15, k16, k17, k18, k19, k1a, k1b, \
	k20, k21, k22, k23, k24, k25, k26, k27, k28, k29, k2a, k2b, \
	k30, k31, k32, k33, k34, k35, k36, k37, k38, k39, k3a, k3b \
	) \
	LAYOUT_grid( \
		KC_##k00, KC_##k01, KC_##k02, KC_##k03, KC_##k04, KC_##k05, KC_##k06, KC_##k07, KC_##k08, KC_##k09, KC_##k0a, KC_##k0b, \
		KC_##k10, KC_##k11, KC_##k12, KC_##k13, KC_##k14, KC_##k15, KC_##k16, KC_##k17, KC_##k18, KC_##k19, KC_##k1a, KC_##k1b, \
		KC_##k20, KC_##k21, KC_##k22, KC_##k23, KC_##k24, KC_##k25, KC_##k26, KC_##k27, KC_##k28, KC_##k29, KC_##k2a, KC_##k2b, \
		KC_##k30, KC_##k31, KC_##k32, KC_##k33, KC_##k34, KC_##k35, KC_##k36, KC_##k37, KC_##k38, KC_##k39, KC_##k3a, KC_##k3b \
    )

#define LAYOUT LAYOUT_grid
#define LAYOUT_ortho_4x12 LAYOUT_grid
#define KC_LAYOUT_ortho_4x12 KC_KEYMAP
#define LAYOUT_kc_ortho_4x12 KC_KEYMAP

#endif