Suggestions

Good job, Cody. 

#### Exercise 1

Works great, 4 points.

* Use 2 spaces instead of 4 :space_invader: 
* There's no need for `while` to test the `bottles` variable since the `break` condition is inside the loop. :zap:
* Use `elsif` to reduce the number of tests made per loop. :alien: 

#### Exercise 2

Works great, 4 points.

* Blank lines help readability :eyes: 

#### Exercise 3

Works great, 4 points.

* Blank lines help readability :eyes: 

#### Exercise 4

So close. It runs without crashing, but it doesn't generate the correct output. 3 points.

* You forgot to handle the case where a year is divisible by 100 and 400. Re-read the question and See http://kalender-365.de/leap-years.php

#### Score

15 out of 16 points :star: