#include <Servo.h>
Servo ser1; Servo ser2;
Servo ser3; Servo ser4;
const int vert  = A7, horz  = A6;
const int vert2 = A5, horz2 = A4;
int       yVal,      xVal;
int       yVal2,     xVal2;
int ang1, ang2, ang3, ang4;

void setup() {
  pinMode(vert, INPUT); pinMode(horz, INPUT);
  ser1.attach(3);       ser2.attach(5);
  ser3.attach(6);       ser4.attach(9); 
  Serial.begin(9600);
}
void loop() {
  xVal  = constrain(analogRead(horz), 100, 900);   
  yVal  = constrain(analogRead(vert), 100, 900);
  xVal2 = constrain(analogRead(horz2), 100, 900);   
  yVal2 = constrain(analogRead(vert2), 100, 900);
  Serial.println(String(xVal) + " | " + String(yVal));
  ang1 = map(xVal,  100, 900, 0, 180);
  ang2 = map(yVal,  100, 900, 0, 180);  
  ang3 = map(xVal2, 100, 900, 0, 180);
  ang4 = map(yVal2, 100, 900, 0, 180);
  ser1.write(ang1);  ser2.write(ang2);
  ser3.write(ang3);  ser4.write(ang4);
}