Mercenary forces became adept at outflanking and then reducing Simba positions with enfilade fire. Pillboxes had caused more delays and subjected the attacking troops to frequent enfilade fire. As the Austrians withdrew, the Prussian artillery raked them with enfilade fire. These positions had embrasures that permitted a wide range of enfilade fire on the beach. The Horse Artillery advanced to the southern flank in an attempt to enfilade the trenches. French fortifications were to be engaged by the heaviest howitzers and enfilade fire. Strafing, firing on targets from a flying platform, is often done with enfilade fire. Ricketts's right flank was pushed back, allowing the Confederates to enfilade the Union line. The destruction of trenches frontally was generally estimated as requiring twice the enfilade amount. The Union forces flanked Pyron's men again and punished them with enfilade fire. It met with fierce German resistance and heavy enfilade fire from the south. The main building has enfilade arrangement and grand main staircase. This enabled enfilade lines of fire and somewhat defiladed the army units themselves. A machine-gun began enfilade fire from the right, causing many casualties. The queen's apartment formed a parallel enfilade with that of the "grand appartement du roi".