make sure a solution always shows up, use "demo" if exists

1-js/06-advanced-functions/03-closure/6-filter-through-function/solution.md

@@ -14,7 +14,7 @@ alert( arr.filter(inBetween(3, 6)) ); // 3,4,5,6
 
 # Filter inArray
 
-```js run
+```js run demo
 function inArray(arr) {
   return function(x) {
     return arr.includes(x);

1-js/06-advanced-functions/03-closure/8-make-army/solution.md

@@ -55,9 +55,9 @@ function makeArmy() {
 
 As a result, all `shooter` functions get from the outer lexical envrironment the same, last value `i=10`.
 
-The fix can be very simple:
+We can fix it by moving the variable definition into the loop:
 
-```js run
+```js run demo
 function makeArmy() {
 
   let shooters = [];
@@ -80,9 +80,9 @@ army[0](); // 0
 army[5](); // 5
 ```
 
-Now it works correctly, because every time the code block in `for (..) {...}` is executed, a new Lexical Environment is created for it, with the corresponding value of `i`.
+Now it works correctly, because every time the code block in `for (let i=0...) {...}` is executed, a new Lexical Environment is created for it, with the corresponding variable `i`.
 
-So, the value of `i` now lives a little bit closer. Not in `makeArmy()` Lexical Environment, but in the Lexical Environment that corresponds the current loop iteration. A `shooter` gets the value exactly from the one where it was created.
+So, the value of `i` now lives a little bit closer. Not in `makeArmy()` Lexical Environment, but in the Lexical Environment that corresponds the current loop iteration. That's why now it works.
 
 ![](lexenv-makearmy.png)
 
@@ -90,7 +90,6 @@ Here we rewrote `while` into `for`.
 
 Another trick could be possible, let's see it for better understanding of the subject:
 
-
 ```js run
 function makeArmy() {
   let shooters = [];