Diamond

diamond

first, last = "A".ord, "D".ord;

rows = (first...last).to_a + last.downto(first).to_a
cols = last.downto(first).to_a + (first + 1..last).to_a

rows.each do |row|
  line = cols.map do |col|
    col == row ? col.chr : "-"
  end
  puts line.join
end

A,Z=65,90;((A...Z).to_a+Z.downto(A).to_a).map{|r|puts (Z.downto(A).to_a+(A+1..Z).to_a).map{|c|c==r ?c.chr: " "}*""}

let c=['A'..'C'];d=reverse c in mapM_ putStrLn$chunksOf 5$(\x y->if(x==y)then x else '-')<$>c++tail d<*>d++tail c

(Although it requires a few imports, so is perhaps cheating ;-) But pretty much everything in Haskell needs a few imports...