Level 23 in 100 Exits is a motion sensor stage that is just screaming for you to shake that device of yours. When you begin the stage in 100 Exits you will see a painting on the wall. Everything else is painted white and well there’s nothing much to see.
If you want to get started on beating level 23 in 100 Exits then you need to shake your device fast left and right to drop the painting. Once you do this you will notice an imperfect following above the green sign, which looks like a hammer. Tap it then a hammer will drop out of the wall onto the floor. After you have the hammer use it to tap in the middle until the wall breaks into a door and for you to get out of Level 23 in 100 Exits!