 There were difficulties getting this episode up to the minimum length of an episode and many scenes were added in post @-@ production . The episode starts with a repeat of a couch gag that was first used in the episode " Lisa 's First Word " , which is considerably longer than the typical couch gag . The crew added an Itchy & Scratchy cartoon and a few misleads as to who was trying to kill Bart. Even with all of these additions , the episode still ran short of time . This led to the creation of the rake sequence , which became a memorable moment of the episode , and the entire series . Originally , Sideshow Bob was only supposed to step on one rake after he stepped out from the underside of the Simpson family 's car , but this was changed to nine rakes in a row . According to executive producer Al Jean , the idea was to make the scene funny , then drag the joke out so that it is no longer funny , and then drag it out even longer to make it funny again . 
