Numeric#step with keyword arguments in JRubyArt (and jruby-9.0.0.0)

Since jruby-9.0.0.0 we can use many syntax features of ruby-2.1, most useful of these for JRubyArt is the ability to make code more readable/reliable with various keyword arguments changes here is one such example:-

# We extend the language of conditionals by adding the
# keyword "elsif". This allows conditionals to ask
# two or more sequential questions, each with a different
# action.

def setup
  background 0
  2.step(by: 2, to: width - 2) do |i|
    # If 'i' divides by 20 with no remainder
    # draw the first line..
    # else if 'i' divides by 10 with no remainder
    # draw second line, else draw third line
    if (i % 20) == 0
      stroke 255
      line i, 80, i, height / 2
    elsif (i % 10) == 0
      stroke 153
      line i, 20, i, 180
    else
      stroke 102
      line i, height / 2, i, height - 20
    end
  end
end

def settings
  size 640, 360
end