YM_3D_ON_MIN
#define YM_EQ_ON_MIN ((YM_3D_ON_MIN >> YM_EQ_REDUCE_BIT) + YM_EQ_FLAT_OFFSET)
#define YM_WIDE_OFF(v) ((v)->left < YM_3D_ON_MIN && (v)->right < YM_3D_ON_MIN)