LEVEL_OFFSET_STEP
int first_row = row, offset = LEVEL_OFFSET_STEP;
int first_row = row, offset = level * LEVEL_OFFSET_STEP;
extra_offset = LEVEL_OFFSET_STEP;
int first_row = row, offset = LEVEL_OFFSET_STEP;
extra_offset = LEVEL_OFFSET_STEP;
extra_offset = LEVEL_OFFSET_STEP;