y = |||x| + 2| - 4|

This function involves triple nested absolute values.

Step 1: Evaluate the innermost expression: |x| + 2. This is always non-negative.

Step 2: Evaluate the next layer: ||x| + 2| - 4. This can be positive or negative.

Step 3: Take the absolute value of the result: y = |||x| + 2| - 4|.