Changed my filter to use a guard rather than an if, since ifs are ugly, right?
A list concat that really really works!
A flatten function
A flatmap implementation
A seqOptional that uses the new let/case pattern matching to see what the result of the recursion was
A find that returns the first element to match if one found, inside a Maybe
A length that is true is greater than 4
A reverse function, and fixing some warnings due to missing patterns