Continuity mistake: In the last shot of Adam beating the Castigliane brothers car with a golf club, we see a flock of birds fly from behind the car in a scare. It's impossible they've stayed there during the whole beating sequence and we don't see them land anywhere near the car during the sequence itself.
Continuity mistake: After the film director discovers his wife in bed with the pool cleaner, he pours pink paint into her jewelry box and splashes it on his hands and suit. He then runs down to his car, opens the door and drives away. The paint would not have had time to dry and would still be wet; however, there are no pink paint marks on the car's door, door handle or in the car itself.
Continuity mistake: When Betty is frightened in the creepy theatre, Rita puts her arm around her at one point from a previous pose of holding hands. We see this in one long shot but in the very next shot of them close up they are back to holding hands.
Continuity mistake: When Betty meets Coco in the court yard at her Aunt Ruth's place, she sets her blue suitcases down and the two enter Ruth's apartment. You can see Betty nor Coco are carrying the bags. Coco leaves and the camera follows Betty as she explores the apartment, finding Rita in the shower. After a few lines of dialogue, Betty says she will unpack. There's a two or three second closeup of Rita's face, then a cut to Betty flinging her blue suitcase onto the bed. She would have had to run to the courtyard, grab her bags and race back to the bedroom in about two seconds.
Continuity mistake: When Rita and Betty put the money away Betty takes the box down and opens it then takes the black hat out. The bag goes in the bottom of the box, the hat follows and the lid goes back on. When they come back for the key the box comes out, the lid comes off and the bag is removed - where did the hat go?
Continuity mistake: When one of the Castigliani brothers slides the envelope over the table, the opening is on the top side, but when Mr Darby gets it, the opening is on the bottom side. (00:29:20)
Answer: Pink colour is sometimes associated with same-sex relationships (eg. the pink stripe on the Bisexual Pride flag is for homosexualism), and lesbian love is one of the main themes in the film. Anyway, David Lynch's imagery is perhaps a little too subtle to be reducible to a code of symbols.