done with 11

examples/counter.lox

@@ -0,0 +1,10 @@
+fn makeCounter() {
+  let i = 0;
+  fn count() {
+    i = i + 1;
+  }
+}
+
+let counter = makeCounter();
+print(counter()); // "1".
+print(counter()); // "2".

examples/fib.lox

@@ -0,0 +1,8 @@
+fn fibonacci(n) {
+  if n <= 1 { return n; }
+  return fibonacci(n - 2) + fibonacci(n - 1);
+}
+
+for let i = 0; i < 25; i = i + 1 {
+  print(fibonacci(i));
+}

examples/thrice.lox

@@ -0,0 +1,9 @@
+fn thrice(f) {
+  for let i = 1; i <= 3; i = i + 1 {
+    f(i);
+  }
+}
+
+thrice(fn (a) {
+  print(a);
+});