"Harley wanted a normal family with Joker hence the baby in her vision. I figured she would have endlessly pestered Mr J about having a kid. SO he had Mr. Frost buy some onesies. The circle represents how he sees Harley." David Ayer, Twitter, 28 MAR 2020.
David Ayer helps us experience the world through Harley Quinn's eyes in this 360 virtual reality featurette [Credit: posted to YouTube by Warner Bros. Home Entertainment].