How to code a "punching wall" obby part

Start with your wall and add whatever stepping blocks you want. In this example, they are round ramps made from wedges
Place a small normal block in the wall, having alittle but poke out the front. Make this neon to let the player know it will be a kill brick.
Selecting our punching kill brick, open up the code builder. From Event add an at start block, followed by a do forever block Control.
Inside, put a wait -- seconds block from Control. Set the seconds to however long you want it to delay. follow it by a tween position in plot block from Motion. Change the seconds to 1 for a fast punch, and enter "-4" into the X input

This depends on which direction you're facing. X= front and back, Z=Left and right. if it doesn't work, simply change the Z input instead

Repeat step 4, however change the seconds to how long you want it to stay out and change the negative input to a positive input to bring the block back.
To the side, turn it into a kill brick by placing a when touched by a player block from Events followed by a change player health block from Player

Your code should look like this!