Average surface density of stellar companions as a function of projected angular separation from each blue star in the whole observed area (blue solid line) and in the region of the vicinity of the H ii region N33 (red dashed line). Error bars are indicated. From both curves, one can distinguish a break in the correlation at almost the same separation of θ ≃ 10″, i.e., 3 pc. This scale separates any large stellar clustering from the small binary/multiple stellar clumps.