The mathematical term “f(x)” sounds like the word “effects.” A joke was posted on Reddit—Dadjokes on March 17, 2019:
   
“I watched a movie about graphs last night, but I was slightly disappointed. The plot was predictable, and the special f(x) was terrible.”
 
“I watched a movie about graphs last night and I was slightly disappointed. The plot was predictable and the special f(x) were terrible”—a slight grammar change—was posted on Twitter by Mister Miracle on March 17, 2019.
 
There are other jokes about “a movie about graphs.” “What do you call a movie about graphs that is all over the place? A scattered plot” was posted on Twitter by 「F a v e s t a r P l a t i n u m」on June 28, 2018.
   
       
Wikipedia: Function (mathematics)
In mathematics, a function was originally the idealization of how a varying quantity depends on another quantity. For example, the position of a planet is a function of time. Historically, the concept was elaborated with the infinitesimal calculus at the end of the 17th century, and, until the 19th century, the functions that were considered were differentiable (that is, they had a high degree of regularity). The concept of function was formalized at the end of the 19th century in terms of set theory, and this greatly enlarged the domains of application of the concept.
 
Twitter
Freshly Made Runny Egg 🥚
@_Ninji
I once watched a movie about graphs which was really badly made… and when I saw the credits, all became clear
Turns out it wasn’t directed
3:25 PM - 21 Nov 2015 from San Roque, Spain
   
Twitter
「F a v e s t a r P l a t i n u m」
@HamadZal
What do you call a movie about graphs that is all over the place? A scattered plot.
2:06 PM - 28 Jun 2018
 
Reddit—Dadjokes
Posted by u/porichoygupto March 17, 2019
I watched a movie about graphs last night, but I was slightly disappointed.
The plot was predictable, and the special f(x) was terrible.
 
Twitter
keepingitcreel
@Keepingitcreel
I watched a movie about graphs last night, but I was slightly disappointed. The plot was predictable, and the special f(x) was terrible.
6:39 AM - 17 Mar 2019
     
Twitter
Mister Miracle
@adam_alkhal
I watched a movie about graphs last night and I was slightly disappointed. The plot was predictable and the special f(x) were terrible 😔
1:42 PM - 17 Mar 2019
 
Twitter
dad.banter
@dad_banter
I watched a movie about graphs last night, but I was slightly disappointed.
The plot was predictable, and the special f(x) was terrible.
1:07 PM - 18 Mar 2019