docs fixes

docs/blocks/loops.md

@@ -0,0 +1,7 @@
+# @extends
+
+### #specific
+
+```
+basic.forever(() => {});
+```

docs/types/var.md

@@ -1,9 +1,49 @@
 # @extends
 
-### #letexample
+#### #letexample
 
 A variable is created for the number returned by the [brightness](/reference/led/brightness) function.
 
 ```block
 let b = led.brightness();
 ```
+
+#### #readvariableexample
+
+For example, the following code shows the value stored in `counter` on the LED screen:
+
+```blocks
+let counter = 1;
+basic.showNumber(counter);
+```
+
+#### #updatevariableexample
+
+The following code sets `counter` to 1 and then increments `counter` by 10:
+
+```block
+let counter = 1;
+counter = counter + 10;
+basic.showNumber(counter);
+```
+
+#### #whyusevariablesexample
+
+A counter is a great example:
+
+```block
+let counter = 0;
+input.onButtonPressed(Button.A, () => { 
+  counter = counter + 1;
+  basic.showNumber(counter);
+});
+```
+
+#### #localvariableexample
+```block
+// x does NOT exist here.
+if (led.brightness() > 128) {
+  // x exists here
+  let x = 0;
+}
+```