This wall reminds me of Laurie Dann, and how she lined students up in a classroom to shoot them, one by one.
Laurie Dann was one of the scariest things that occurred during my childhood. It took me years to get over the fright of what this woman did at a school near mine.
Here's the story from 1988:
30-year-old Dann arrived at the home of former babysitting clients in Winnetka, Illinois to pick up the youngest two children. Instead of taking them on the promised outing, she took them to Ravinia Elementary School in Highland Park, Illinois, and left them in the car while she entered the school and tried to detonate a fire bomb in one of the school's hallways. The small fire she set was quickly extinguished by a teacher. Returning her two passengers to their home, she offered them some arsenic-poisoned milk, but the boys spat it out as it tasted strange. Once at their home, she used gasoline to set fire to the house, briefly trapping the mother and her two children in the basement. She then drove three and a half blocks to the Hubbard Woods School carrying three handguns. She wandered into and observed a second grade classroom for a short while, then left and finding a boy in the corridor, pushed him into the boys' washroom and shot him with a .22 semi-automatic Beretta pistol. Her .357 Smith and Wesson Magnum revolver jammed as she tried to fire it at two other boys in the washroom, and she threw it into the washbasin along with the spare ammunition she had brought. The boys ran out of the washroom and raised the alarm. Dann then re-entered the same second grade classroom where the students were working in groups on a bicycle safety test. She ordered all the children into the corner of the room, but the teacher refused, and attempted to disarm Dann, managing to unload the Beretta in the struggle. Dann drew a .32 Smith and Wesson from the waistband of her shorts and shot at several groups of the students. She killed eight-year-old Nicholas Corwin, and wounded two girls and two boys before fleeing in her car.