4-D is dedicated to the memory of Ricky Loyd Arreguin (real name was Ricardo David Loyd), who was murdered by a gang on his way home from John F. Kennedy High (Los Angeles). He had been walking in the 11100 block of Woodley Avenue with a group of students just after 3 p.m. A red car pulled up and an armed man jumped out, asking if anyone was in a gang. Despite no one saying they were, "the suspect fired.l". The gunman "reached over the fence and shot him in the head". Ricky Loyd had been walking from the high school down the block to meet his mother, Dorene Arreguin, who was waiting where she always picked him up. Ricky's stepfather, Jose Arreguin, works on props for the Fox television series "The X-Files". UPDATE: San Fernando jury convicted 19-year-old Victor Manuel Celis of second-degree murder, gang and firearms allegations. He was sentenced to 25 years to life in prison for the fatal shooting of a Kennedy High School student, Ricky Loyd Arreguin September 13, 2001. The second suspect, Hector Ramirez, was also found guilty by a jury in the murder of 16 year old Ricky Loyd Arreguin and sentenced to 35 years to life in prison. He had shot Ricky in the head and kicked him while he lay dying.
This was the first episode to be produced and aired after the events of 9/11.
Writer Steven Maeda was inspired to write this episode after hearing about French journalist Jean-Dominique Bauby, whose locked-in condition was depicted in the film The Diving Bell and the Butterfly (2007).
The title not only refers to the fourth dimension but also to Lukesh's apartment number.
Albert Einstein posited in his theory of relativity that time is the fourth dimension (4-D) after height, width, and depth.