The unicode characters that are placed in the URL or JSON representation of a given circuit for X- and Y-controls are opposite to the ones that are displayed visually in quirk.

For example, examine the following URL https://algassert.com/quirk#circuit={"cols":[["⊖"],["⊕"],["⊗"],["(/)"]]} . If you follow the link and look at the controls actually placed on the circuit, you will notice that the positive and negative version of each control is flipped. That is to say, this URL actually encodes [["⊕"],["⊖"],["(/)"],["⊗"]] as would appear in Quirk.