How to unscrew this square screw?

Phillips Screwdriver; Torx Screwdriver; Hex Screwdriver or Hexagon Screwdriver; Robertson or Square Screwdriver; Pozidriv Screwdriver; Clutch Head or Bow Tie

square, Torx® and spanner Use a slotted screwdriver for slotted, combination and one way screws; a Phillips screwdriver for Phillips and

square slot cutter 20 piece Stanley Screwdriver Set STANLEY® Multifunctional Screwdriver Set 0-62

888 slot machine Phillips Screwdriver; Torx Screwdriver; Hex Screwdriver or Hexagon Screwdriver; Robertson or Square Screwdriver; Pozidriv Screwdriver; Clutch Head or Bow Tie