AND gates output 1 if both inputs are 1; if either input is 0, these gates output 0.

OR gates output 1 if one or both inputs is 1; if both inputs are 0, these gates output 0.

XOR gates output 1 if the inputs are different; if the inputs are the same, these gates output 0.

Used for collecting successful swaps.

A variable, with either a value (constants, e.g., x and y vars), or an operation with left & right sides, and operator XOR/OR/AND.