What would happen if there was a way to build walls that reflect any attack that hits it?

For example, a laser blast will bounce back to the person who fired it, a bullet hits the wall and ricochets straight into the person who shot it, a solid punch will cause the same force to be applied back to the person who is punching the wall.<br><br>I'd imagine this would have a massive impact on every aspect of life, from knitting and crocheting (why on earth would we design a dangerous needle that can hurt you?!), to combat in war, to the use of deadly chemicals.<br><br>How would this affect society, and what other examples can you think of?<br><br>Additional rules to help clarify:<br><br>* The force of the attack will never get lost. If you throw a knife at it, you will be hit with a knife sinking into you with the same force as it hit the wall.<br>- The force of the attack will only be applied to the person who initially hit the wall, not the people around them. It's not like shooting the wall with a bullet will cause the people around the target to be shot with a bullet.<br>- The type of attack will also be reflected. If someone shoots the wall with an incendiary bullet, it will light the attacker on fire. <br>- The reflected attack will always target the person who shot the wall. If someone shoots it at point blank range, the bullet will be reflected into the barrel of the gun, which will then explode inside the gun. But if they shoot it from a distance, the bullet will be reflected at the same trajectory as when it left the gun. This goes for things like fist attacks as well. The initial force of the fist will cause the ground to also be moved, but the reflected attack will not cause the ground to move again, but instead will directly apply the force of the fist back to the attacker.<br>- The person reflecting the attack is not invincible, it just reflects any attack that hits it. It could be vulnerable to things like dry rot with a wood wall, or rust with a metal wall.