copysign()

double copysign(double x, double y);

void setup() {
    pinLabel(0, "INY");  // set the label of pin 0 to "INY"
    pinLabel(1, "INX");  // set the label of pin 1 to "INX"
    pinLabel(2, "OUT");  // set the label of pin 2 to "OUT"
    pinMode(2, OUTPUT);  // set pin 2 as output
    pinLabel(3, "OUT2"); // set the label of pin 3 to "OUT2"
    pinMode(3, OUTPUT);  // set pin 3 as output
    
    pinLabel(4, "VCC");  // set the label of pin 3 to "VCC"
    powerPin(4);         // set pin 4 as power pin
    pinLabel(5, "GND");  // set the label of pin 4 to "GND"
    groundPin(5);        // set pin 5 as ground pin
}

void loop() {
    // read the value of the potentiometers
    int val_x = analogRead(0); 
    int val_y = analogRead(1);
    // map the value of the potentiometers from 0 to 1023
    // to the range of -10 to 10
    double x = map(val_x, 0, 1023, -10, 10);
    double y = map(val_y, 0, 1023, -10, 10);
    // calculate the value of x with the sign of y
    double z = copysign(x, y);
    // map the value of z from -10 to 10 to 0 to 1023
    int pwm = (int) map(z, -10, 10, 0, 1023);
    // write the PWM value to pin 2
    analogWrite(2, pwm);
}