foreach loops

With the foreach loop, you are looping through the $colors array and assigning the value of each element (color) to a new variable. So you aren't renaming the $colors array, you are giving a variable name to temporarily represent the individual elements as they are looped through. If you had:

<?php
foreach ($colors as $color) {
 echo $color;
} 

each individual color would be temporarily stored in the $color variable, but that variable would be overwritten after each iteration.

You could use a traditional for loop, in which case you access the the values by using the array index.

<?php

for ($i = 0;  $i < count($colors); $i++) {
  echo $colors[i]
}

The $color variable in the first example is essentially equivalent to saying $color = $colors[i] for each respective iteration, in which case the value of $color would be replaced at each iteration. Hopefully that makes sense :)