Discuss Intertextuality in Shrek and will explain why this animated cartoon is intertextual? and does this movie has changed my views if yes then how?

Intertextuality in Shrek

Intertextuality is something which changes the meaning of any text to another. There are many ways through which this can be taken place, like allusions, parody are few of those techniques.  discuss Intertextuality in Shrek and will explain why this animated cartoon is intertextual? and does this movie has changed my views if yes then how?