More striking vector example

exercises/week02.md

@@ -60,12 +60,12 @@ int special_add(int a, int b){
 }
 ```
 
-10. **(optional)** Have you heard about vectorization before? Declare the function provided below and set the flags to **-O2** and observe how the asembly code differs to having set the flags to to **-O2** **-mavx**
+10. **(optional)** Have you heard about vectorization before? Declare the function provided below and set the flags to **-O1**, **-O2** and observe how the asembly code differs to having set the flags to to **-O2** **-mavx**. Now change the size of the loop, try 4, 8, 16. How many add-operations are run in the assembly?
 
 ```c
-void add_arrays(float *a, float *b, float *result, int n) {
-    for (int i = 0; i < n; i++) {
-        result[i] = a[i] + b[i];
+void add_arrays(float *a, float b) {
+    for (int i = 0; i < 8; i++) {
+        a[i] += b;
     }
 }
 ```