user58222: Using the FastLED library, I want to light up multiple lights at once. 
Currently I am passing in just one light to the function. 
spell( int LEDNumber )
{
  FastLED.clear();
  leds[LEDNumber] = CRGB (255,255,255); //white
  FastLED.show();
  time = 500;
  delay(t);
}

I would like to pass in more than just 1 light at a time. 

user58222: Easier than I thought. Found it while reading the docs. Imagine that. :) 
To pass in multiple variables, just separate them with a comma. 
Docs: https://www.arduino.cc/en/Reference/FunctionDeclaration
Relevant code:
int myMultiplyFunction(int x, int y){
  int result;
  result = x * y;
  return result;
}


user30341: You may create a struct with "x" elements, one for each LED:
struct ArrayOfBooleans {
   bool array[4];
};

ArrayOfBooleans myOutputArray;
myOutputArray.array[0] = true;
myOutputArray.array[1] = true;
myOutputArray.array[2] = false;
myOutputArray.array[3] = true;

lightEmUp(myOutputArray);

void lightEmUp(ArrayOfBooleans myOutputArray) {
   bool isFirstLightOn = myOutputArray.array[0];
   // etc
}

NoTE: If you run into Exception 9 issues (using this logic on another board), please check this answer to another post

58222: <p>Using the FastLED library, I want to light up multiple lights at once. </p>

<p>Currently I am passing in just one light to the function. </p>

<pre><code>spell( int LEDNumber )
{
  FastLED.clear();
  leds[LEDNumber] = CRGB (255,255,255); //white
  FastLED.show();
  time = 500;
  delay(t);
}
</code></pre>

<p>I would like to pass in more than just 1 light at a time. </p>
 58222: <p>Easier than I thought. Found it while reading the docs. Imagine that. :) </p>

<p>To pass in multiple variables, just separate them with a comma. </p>

<p>Docs: <a href="https://www.arduino.cc/en/Reference/FunctionDeclaration" rel="nofollow noreferrer">https://www.arduino.cc/en/Reference/FunctionDeclaration</a></p>

<p>Relevant code:</p>

<pre><code>int myMultiplyFunction(int x, int y){
  int result;
  result = x * y;
  return result;
}
</code></pre>
 30341: <p>You may create a <code>struct</code> with "x" elements, one for each LED:</p>

<pre><code>struct ArrayOfBooleans {
   bool array[4];
};

ArrayOfBooleans myOutputArray;
myOutputArray.array[0] = true;
myOutputArray.array[1] = true;
myOutputArray.array[2] = false;
myOutputArray.array[3] = true;

lightEmUp(myOutputArray);

void lightEmUp(ArrayOfBooleans myOutputArray) {
   bool isFirstLightOn = myOutputArray.array[0];
   // etc
}
</code></pre>

<p>NoTE: If you run into <code>Exception 9</code> issues (using this logic on another board), please check <a href="https://arduino.stackexchange.com/a/67450/30341">this answer to another post</a></p>
